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The chemistry of the elements is heavily altered by high pressure, with stabilization of many new and often unexpected compounds, the emergence of which can profoundly change models of planetary interiors, where high pressure reigns. The C-H-O system is one of the most important planet-forming systems, but its high-pressure chemistry is not well known. Here, using state-of-the-art variable-composition evolutionary searches combined with quantum-mechanical calculations, we explore the C-H-O system at pressures up to 400 GPa. Besides uncovering new stable polymorphs of high-pressure elements and known molecules, we predicted the formation of new compounds. A 2CH4:3H2 inclusion compound forms at low pressure and remains stable up to 215 GPa. Carbonic acid (H2CO3), highly unstable at ambient conditions, was predicted to form exothermically at mild pressure (about 1 GPa). As pressure rises, it polymerizes and, above 314 GPa, reacts with water to form orthocarbonic acid (H4CO4). This unexpected high-pressure chemistry is rationalized by analyzing charge density and electron localization function distributions and implications for general chemistry and planetary science are also discussed.

The electronic and spatial structures of alkali metal compounds CO3M2, CO3M3 +, and CO4M4 (M = Li, Na, K) were investigated by the ab initio (MP2(full)/6-311+G**) and density functional (B3LYP/6-311+G**) methods. The calculated energies of formation decrease in the order E Li > E Na > E K for all structural types, being determined by steric and orbital interactions. Stable structures with octacoordinate carbon are formed in the case of CO4M4 salts.

This volume contains three chapters reviewing 12 classes of organic compounds called esters. This chapter (Chapter 57) reviews esters of monocarboxylic acids and mono- and polyalcohols and esters of alkenyl carboxylic acids and monoalcohols; Chapter 58 reviews esters of aromatic monocarboxylic acids and monoalcohols, esters of monocarboxylic acids and di-, tri-, and polyalcohols, dicarboxylic acid esters, alkenyl dicarboxylic esters, esters of aromatic diacids, and tricarboxylic acid esters; and Chapter 59 covers esters of carbonic acid and orthocarbonic acid, esters of organic phosphorous compounds, esters of monocarboxylic halogenated acids, alkanols, or haloalcohols, and organic silicon esters. The sequence of the compounds has been organized according to the chemical structure of the major functional metabolites. This involves the ester hydrolyzates, primarily the acid and secondarily the alcohol. The reason for this sequence was the general observation that the degree of toxic effect, in addition to that of the original material, more often was the result of the toxicity of the acid rather than the response of the alcohol. Esters are important from an industrial hygiene perspective since exposure can occur during the process of manufacturing esters, the process of manufacturing materials containing or composed of esters, handling and use of products containing or composed of esters, and treatment of wastes containing esters. In turn, exposure to esters is important from a toxicological perspective because of the correlated observations of adverse physiological responses exhibited by laboratory animals and humans. Overviews of the physical, chemical, and toxicological (i.e., physiological responses) properties of many subclasses of esters and/or of specific compounds are provided. In addition, summaries of relative manufacturing and use information are included for many compounds. Chemically, esters are organic compounds commonly formed via the combination of an acid, typically an organic (COOH) mono- or polyacid, and a hydroxyl (OH) group of a mono- or polyalcohol or phenol; water (HOH) is generated as a by-product of the reaction. The esters are widely used in industry and commerce. They can be prepared by the reactions of acids with alcohols by reacting metal salts of acids with alkyl halides, acid halides with alcohols, or acid anhydrides with alcohols by the interchange of radicals between esters. Most esters exist in liquid form at ambient temperatures, but some possess lower boiling points than their original starting materials. They are relatively water insoluble, except for the lower molecular weight members. Their flash points are in the flammable range. The monocarboxylic acid esters have high volatility and pleasant odors, whereas the di- and polyacid esters are relatively nonvolatile and exhibit essentially no odor. The monocarboxylic esters occur frequently in natural products, as, for example, in fruits, to which they lend their pleasant odor and taste. Because of the different properties of esters from the original acids and alcohols, esterification can be used for their isolation or for chemically protecting specific carboxy or hydroxy functions. Absorbed esters and/or metabolites derived from biotransformed esters can initiate toxic effects in some mammalian systems, including humans, and cause adverse physiological responses. Indeed, the underlying causes of physiological responses are due to initial interactions biochemically within a system. Within these chapters, a summary of reviewed literature will reveal that, in general, toxic effects associated with exposure to various esters include primary irritation to ocular, upper and lower respiratory, and dermal systems; depression of the central nervous system (CNS) (e.g., anesthesia and narcosis); dermal hypersensitization; impact to the gastrointestinal, hepatic, and renal systems; abnormal cardiac rhythm; and carcinogenesis. Indeed, these and some additional effects are based predominantly on rodent studies. A review of the literature reported here, however, indicates that the most commonly reported effects in animals and humans are irritation and, to some extent, CNS depression. Data are reported in this chapter for several classes of esters, including formates, acetates, acrylates and methacrylates, propionates, and lactates. Most of the aliphatic esters possess some degree of irritation on exposed surfaces. Practically all the common aliphatic and aromatic esters, except for some phosphates used as plasticizers, are inert. At the most, minor degrees of irritation may follow inhalation of heated vapors or prolonged skin exposure. Some of the literature also suggests that reported skin sensitization appears more likely in the presence of impurities or side products. Many of the materials are so inert that any LD50 value is impractical to determine. Specific pathology is usually absent even when the materials are fed in massive quantities to the point of nutritional deprivation. Oily or watery excretion products, sometimes observed at high feeding levels, indicate lack of absorption. The apparent nontoxicity may also be a sign of rapid hydrolysis, metabolism, and excretion. The resins are completely inert, unabsorbed in the gastrointestinal tract, and nonirritant at the surface of the skin and pulmonary system. Keywords: acetates; acetoacetals; acrylates; alkyl carboxylic acids; butyrates; formates; inhalation; lactates; methacrylates; propionates; sugarcane

This chapter covers (1) esters of carbonic and orthocarbonic acid, (2) esters of organic phosphorous compounds, (3) esters of monocarboxylic halogenated acids, alkanols, or haloalcohols, and (4) organic silicon esters. Other classes of esters are summarized in Chapters 57 and 58. Refer to the Introduction in Chapter 57 for a more detailed overview of general properties of esters. Unfortunately, as shown in the two prior chapters, mainly fragmented toxicological evaluations are available for esters. Most of these esters are characterized by low toxicity. Indeed, as expressed in Chapter 57, lethal dose (e.g., LD50) values are frequently difficult or impractical to measure. Localized dermal irritation is one common effect characteristic of exposures to most organic solvents. Few esters are readily absorbed, but there are exceptions, such as tri-o-cresyl phosphate (TOCP). Several of the halogenated derivatives, such as ethylchloro- and ethylbromo-, are potent lacrimators. Ethyl fluoroacetate and fluoroacetic acid exhibit about the same mode of action, which may indicate that the acetate is rapidly hydrolyzed and metabolized in the mammalian system. The unsaturated carbonates are also associated with high lacrimatory activity. TOCP is an example of an ester that can cause neuropathy in a variety of animal species. The initial weakness and paralysis are normally reversible in early stages, but repeated or massive assaults result in demyelination of the nerve fibers. The mechanism of action is not yet certain, but it appears to involve phosphorylation of proteins. Only selected phosphates exhibit neuropathic effects, including diisopropyl fluorophosphorate and N,N′-diisopropyl phosphorodiamidic fluoride. As was expressed in Chapter 57, industrial hygiene evaluation of esters involves collecting and analyzing air samples to determine their airborne concentrations. Published industrial hygiene air sampling and analytical methods, however, are unavailable for most esters. In relation, there are few occupational exposure and biological limits. A list of ester compounds covered in this chapter that have industrial hygiene sampling and analytical methods are presented here along with their respective occupational exposure limits, established by the American Conference of Governmental Industrial Hygienists (ACGIH), the Occupational Safety and Health Administration (OSHA), and the National Institute for Occupational Safety and Health (NIOSH). As stated in Chapter 57, since sampling and analytical methods and occupational exposure limits are subject to periodic revision, the reader is encouraged to refer to current publications of ACGIH, OSHA, and NIOSH. Keywords: alkyl phosphates; alkyl phosphines; aryl phosphates; aryl phosphines; bromoesters; carbonates; chloroesters; cyclic carbonates; esters of organic phosphorus compounds; fluroesters; haloalcohols; halogenated phosphate esters; organic silicon esters; ortho acid esters; silanal esters; silanes

This volume contains three chapters reviewing 12 classes of the organic compounds called esters. Chapter 79, this chapter, reviews (1) esters of monocarboxylic acids and mono- and polyalcohols and (2) esters of alkenyl carboxylic acids and monoalcohols; Chapter 80 reviews (3) esters of aromatic monocarboxylic acids and monoalcohols, (4) esters of monocarboxylic acids and di-, tri-, and polyalcohol; (5) dicarboxylic acid esters; (6) alkenyl dicarboxylic esters; (7) esters of aromatic diacids; (8) tricarboxylic acid esters; and, Chapter 81 covers (9) esters of carbonic and orthocarbonic acid; (10) esters of organic phosphorous compounds; (11) esters of monocarboxylic halogenated acids, alkanols, or haloalcohols; and (12) organic silicon esters. The sequence of the compounds has been organized according to the chemical structure of the major functional metabolites. This involves the ester hydrolyzates, primarily the acid and secondarily the alcohol. The reason for this sequence was the general observation that the degree of toxic effect, in addition to that of the original material, more often was the result of the toxicity of the acid rather than the response of the alcohol. Esters are important from an industrial hygiene perspective since exposure can occur during the process of manufacturing esters, the process of manufacturing materials containing or composed of esters, handling and use of products containing or composed of esters, and treatment of wastes containing esters. In turn, exposure to esters is important from a toxicological perspective because of the correlated observations of adverse physiological responses exhibited by laboratory animals and humans. Overviews of the physical, chemical and toxicologic (i.e., physiologic responses) properties of many subclasses of esters and/or of specific compounds are provided. In addition, summaries of relative manufacturing and use information are also included for many compounds. Chemically, esters are organic compounds commonly formed via the combination of an acid, typically an organic (COOH) mono- or polyacid, plus a hydroxyl (OH) group of a mono-or polyalcohol or phenol; water (HOH) is generated as a by-product of the reaction. The esters are widely used in industry and commerce. They can be prepared by the reactions of acids with alcohols, by reacting metal salts of acids with alkyl halides, acid halides with alcohols, or acid anhydrides with alcohols by the interchange of radicals between esters. Most esters exist in liquid form at ambient temperatures, but some possess lower boiling points than their original starting materials. They are relatively water-insoluble, except for the lower molecular weight members. Their flash points are in the flammable range. The monocarboxylic acid esters have high volatility and pleasant odors, whereas the di- and polyacid esters are relatively nonvolatile and exhibit essentially no odor. The monocarboxylic esters occur frequently in natural products, as, for example, in fruits, to which they lend their pleasant odor and taste. Because of the different properties of esters from the original acids and alcohols, esterification can be used for their isolation or to chemically protect specific carboxy or hydroxy functions. Absorbed esters and/or metabolites derived from biotransformed esters can initiate toxic effects in some mammalian systems, including humans, and cause adverse physiological responses. Indeed, the underlying causes of physiological responses are due to initial interactions biochemically within a system. Within these chapters, a summary of reviewed literature will reveal that, in general, toxic effects associated with exposure to various esters include primary irritation to ocular, upper and lower respiratory, and dermal systems; depression of the central nervous system (CNS) (e.g., anesthesia, narcosis); dermal hypersensitization; impact to the gastrointestinal (GI), hepatic, and renal systems; abnormal cardiac rhythm; and carcinogenesis. Indeed, these and some additional effects, are based predominantly on rodent studies. A review of the literature reported here, however, indicates that the most commonly reported effects in animals and humans are irritation and, to some extent, CNS depression. Data are reported in this chapter for several classes of esters, including formates, acetates, acrylates and methacrylates, propionates, and lactates. Most of the aliphatic esters possess some degree of irritation on exposed surfaces. Practically all the common aliphatic and aromatic esters, except for some phosphates used as plasticizers, are inert. At the most, minor degrees of irritation may follow inhalation of heated vapors or prolonged skin exposure. Some of the literature also suggests that reported skin sensitization appears more likely in the presence of impurities or side products. Many of the materials are so inert that any LD50 value is impractical to determine. Specific pathology is usually absent, even when the materials is fed in massive quantities to the point of nutritional deprivation. Oily or watery excretion products, sometimes observed at high feeding levels, indicate lack of absorption. The apparent nontoxicity may also be a sign of rapid hydrolysis, metabolism, and excretion. The resins are completely inert, unabsorbed in the gastrointestinal tract, and nonirritant at the surface of the skin and pulmonary system. Keywords: Formates; Acetates; Inhalation; Acetoacetals; Propionates; Butyrates; Sugarcane; Alkyl carboxylic acids; Acrylates; Methacrylates; Lactates

This chapter covers (1) esters of carbonic and orthocarbonic acid, (2) esters of organic phosphorous compounds, (3) esters of monocarboxylic halogenated acids, alkanols, or haloalcohols, and (4) organic silicon esters. Other classes of esters are summarized in Chapters 79 and 80. Refer to the Introduction in Chapter 79 for a more detailed overview of general properties of esters. Unfortunately, as shown in the two prior chapters, mainly fragmented toxicological evaluations are available for esters. Most of these esters are characterized by low toxicity. Indeed, as expressed in Chapter 79, lethal dose (e.g., LD50) values are frequently difficult or impractical to measure. Localized dermal irritation is one common effect characteristic of exposures to most organic solvents. Few esters are readily absorbed, but there are exceptions, such as tri-o-cresyl phosphate (TOCP). Several of the halogenated derivatives, such as ethylchloro- and ethylbromo-, are potent lacrimators. Ethyl fluoroacetate and fluoroacetic acid exhibit about the same mode of action, which may indicate that the acetate is rapidly hydrolyzed and metabolized in the mammalian system. The unsaturated carbonates are also associated with high lacrimatory activity. TOCP is an example of an ester that can cause neuropathy in a variety of animal species. The initial weakness and paralysis are normally reversible in early stages, but repeated or massive assaults result in demyelination of the nerve fibers. The mechanism of action is not yet certain, but it appears to involve phosphorylation of proteins. Only selected phosphates exhibit neuropathic effects, including diisopropyl fluorophosphorate and N,N′-diisopropyl phosphorodiamidic fluoride. As was expressed in Chapter 79, industrial hygiene evaluation of esters involves collecting and analyzing air samples to determine their airborne concentrations. Published industrial hygiene air sampling and analytical methods, however, are unavailable for most esters. In relation, there are few occupational exposure and biological limits. A list of ester compounds covered in this chapter that have industrial hygiene sampling and analytical methods are presented here along with their respective occupational exposure limits, established by the American Conference of Governmental Industrial Hygienists (ACGIH), the Occupational Safety and Health Administration (OSHA), and the National Institute for Occupational Safety and Health (NIOSH). As stated in Chapter 79, since sampling and analytical methods and occupational exposure limits are subject to periodic revision, the reader is encouraged to refer to current publications of ACGIH, OSHA, and NIOSH. Keywords: Cyclic carbonates; Carbonates; Ortho acid esters; Esters of organic phosphorus compounds; Alkyl phosphines; Aryl phosphines; Alkyl phosphates; Aryl phosphates; Halogenated phosphate esters; Haloalcohols; Chloroesters; Bromoesters; Fluroesters; Organic silicon esters; Silanes; Silanal esters

The title compound (systematic name: 4,7-methano-2,2′-spirobi­[1,3-benzodioxole]), C14H14O4, is an asymmetric spiro ester of orthocarbonic acid and two diols, viz. the aromatic benzene-1,2-diol and the aliphatic vicinal norbornane-exo-cis-2,3-diol. The orthocarbonate mol­ecule is close to having non-crystallographic C s symmetry. The five-membered ring stemming from the aliphatic diol has an envelope conformation. C—O bonds including the spiro-C atom span an approximately 0.07 Å range, but are within 0.02 Å of the respective distances in a density functional theory calculation, i.e. the distance difference is not caused by packing forces. Accordingly, the crystal packing is characterized by weak C—H⋯O and C—H⋯π inter­actions.

The title compound, C13H10Cl2O2, is a mixed derivative of orthocarbonic acid. The non-crystallographic symmetry of the molecule is close to C2v. The aromatic residues are oriented in a syn conformation with respect to the Cl atoms. The least-squares planes through the phenyl rings enclose an angle of 36.11 (10)°. The C—O bonds at the central carbon are relatively short, and the O—C—O and Cl—C—Cl angles are smaller than the tetrahedral angle. These metrical peculiarities including a molecular symmetry close to C2v are also observed in density functional theory (DFT) calculations, thus ruling out the decisive influence of intermolecular forces in the crystal structure. Accordingly, only few and weak intermolecular interactions are found. At distances smaller than the sum of the van der Waals radii, only two attractive interactions are detected: a weak C—H...O and a weak C—H...Cl hydrogen bond to one of the two potential acceptor atoms each.

The title compound, C13H16O4, is a mixed orthocarbonic acid ester derived from the alcohol components benzene-1,2-diol and 2,3-dimethyl­butane-2,3-diol (pinacol). The spiro­cyclic mol­ecules exhibit noncrystallographic C2 symmetry. The C—O bonds between the spiro centre and the aliphatic di­oxy fragment are markedly shorter than the bonds to the aromatic residue. Neither steric strain, which equalizes the bond lengths in a glucoside analogue, nor the packing of the mol­ecules in the crystal structure are responsible for the large C—O bond-length range, which obviously is a mol­ecular property.

The title compound, C21H20O8, is the mixed orthocarbonic acid ester of the alcohol components benzene-1,2-diol and 4,6-O-benzyl­idene-1-O-methyl-α-d-glucopyran­oside. The compound represents the first example of a structurally characterized carbohydrate ester of orthocarbonic acid. Both oxacyclic six-membered rings in the structure adopt a chair conformation. The puckered five-membered ring at the spiro centre is present in a twist conformation. No special inter­actions are observed in the mol­ecular packing.

Aus Trimethoxyessigsaure-methylester (1) und cis-1,3,5-Cyclohexantriol (2) ist 2,4,10-Trioxaadamantan-3-carbonsaure-methylester (3) leicht zuganglich. Aus 3 werden weitere Derivate des 2,4,10-Trioxaadamantans erhalten. Durch Abbaureaktionen gelangt man zu 3-Brom- und 3-Amino-2,4,10-trioxaadamantan 20, 21. Beide sind neue Orthokohlensaureabkommlinge mit bisher unbekannten Strukturelementen. Compounds with Urotropine Structure, LX. – Orthooxalic and Orthocarbonic Acid Derivatives with Adamantane Structure Methyl trimethoxyacetate (1) and cis-1,3,5-cyclohexanetriol (2) easily react to give methyl 2,4,10-trioxaadamantane-3-carboxylate (3). Based on 3, further derivates of 2,4,10-trioxaadamantane are prepared. By degradation reactions, 3-bromo- and 3-amino-2,4,10-trioxaadamantane 20 and 21 are obtained. Both are new derivates of orthocarbonic acid, their structure elements being unknown up to now.

Das Orthokohlensaurederivat 5 reagiert mit den schwachen CH-aciden Verbindungen 4a-h zu den Ketenaminalen 6a-h. Die Verbindung 6i entsteht aus N,N,N',N',N”,N”-Hexamethyl-guanidiniumchlorid und 4i in Gegenwart von Natriumhydrid. Aceton setzt sich mit 5 auch zum Bis(ketenaminal) 7 um. Die Methylbenzophenone 8a, b liefern mit 5 die Vinylidendiamine 9a, b. N,N-(Dimethyl)thioacetamid (15), der Iminoester 16 ebenso wie das Lacton 24, das Lactam 25 und die Thiolactame 26, 27 werden durch 5 in die Ketenaminale 19, 20 und 28–31 ubergefuhrt. Entsprechende Umsetzungen von 5 mit CH-aciden Methylheterocylen liefern die Vinylidendiamine 32, 34, 35, 40, 41, 43 und 44. Orthoamides, XXXIX -Preparation of Ketene Aminals from CH-acidic Compounds and Ethoxy-N,N,N′,N′,N″,N″-hexamethylmethanetramine The orthocarbonic acid derivative 5 reacts with the weakly CH-acidic compounds 4a-h to give the ketene aminals 6a-h. The compound 6i has been obtained from 4i and N,N,N',N',N“N”-hexamethylguanidinium chloride in the presence of sodium hydride. Acetone reacts with 5 also to give the bis(ketene aminal) 7. Reaction of the methylbenzophenones 8a, b with 5 yields the vinylidenediamines 9a, b. N,N-(Dimethyl)thioacetamide (15), the imino ester 16, as well as the lactone 24, the lactam 25, and the thiolactams 26, 27 are transformed by 5 into the corresponding ketene aminals 19, 20, and 28–31. Analogous reactions between 5 and CH-acidic methyl heterocycles afford the vinylidenediamines 32, 34, 35, 40, 41, 43, and 44

Bei der Umsetzung von cis-Benzoltrioxid (1) mit Guanidin in gepufferter tert-Butylalkohol-Losung werden mit 88 – 91% (9 – 12%) Ausbeute die aus der 1,3(1,2)-Uberbruckung in 1 hervorgehenden 1:1-Addukte DL-(1α,2β,4β,5α,6α,10α)- 8-Imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decan5,10-diol (13a) und DL-(1α,2α,3β,5β,6α,7α)- 9-Imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decan-2,6-diol (12a) gewonnen. Auch Trifluoracetamidin (Acetamidin) wird an 1 bevorzugt 1,3-addiert. Aus 13a gewinnt man durch jeweils regiospezifische Hydrolyse (26a), Thiolyse (30a, d), Ammonolyse (34a), Hydrazinolyse (34d) und HCl/HBr-Addition (39a, c) Zugang zu hochfunktionalisierten 2,4-Diazabicyclo[3.3.1]nonan-Derivaten. Bei der fur 26a und 34d beobachteten „Ring-Ketten-Tautomerie” (28a, 36d) sind die adamantoiden Orthokohlensaure-Intermediate (27a, 35d) nicht nachweisbar. Die u. a. wegen der konformativen Flexibilitat der Geruste nicht immer eindeutigen spektroskopischen Strukturzuordnungen werden durch Rontgenstrukturanalysen fur 29f, 36e, 38 und 43 gesichert. 2,4-Diazabicyclo[3.3.1]nonane Skeletons from cis-Benzene Trioxide By treating cis-benzene trioxide (1) with guanidine in buffered tert-butyl alcohol solution the 1:1-adducts DL-(1α,2β,4β,5α,6α,10α)- 8-imino-3-oxa-7,9-diazatricyclo[4.3.1.02,4]decane-5,10-diol (13a) and DL-(1α,2α,3β,5β,6α,7α)- 9-imino-4-oxa-8,10-diazatricyclo[5.3.0.03,5]decane-2,6-diol (12a) resulting from 1,3(1,2)-bridging in 1 are obtained in 88 – 91% (9 – 12%) yields. Trifluoroacetamidine (acetamidine) is also selectively 1,3-added to 1. From 13a via generally regiospecific hydrolysis (26a), thiolysis (30a, d) ammonolysis (34a), hydrazinolysis (34d), and HCl-/HBr- addition (39a, c) access to highly functionalised 2,4-diazabicyclo[3.3.1]nonane derivatives is opened. During the “ring-chain tautomerism” observed for 26a and 34d (28a, 36d) the adamantoid orthocarbonic acid intermediates (27a, 35d) cannot be identified directly. The spectroscopic structure elucidations (not always unequivocal because i.a. of conformational flexibility of the skeletons) are confirmed by X-ray structural analysis for 29f, 36e, 38, und 43.

Bernsteinsauredinitril (5a) reagiert mit dem Orthokohlensaurederivat 1a zu dem Guanidiniumsalz 6. Glutarsauredinitril (5b) ergibt bei der Umsetzung mit 1a das Benzonitril 9. Adipinsauredinitril (5c) und Pimelinsauredinitril (5d) setzen sich mit 1a zu den En-Guanidinonitrilen 10a, b um. Die hoheren Dinitrile 5e – h kondensieren mit 1a zu den Ketenaminalen 11a – d. Die En-Guanidinonitrile 10 werden durch Alkylierungsmittel in die Guanidiniumsalze 13 ubergefuhrt. Orthoameisensaurederivate 3 reagieren mit den Dinitrilen 5 zu den Enamino-dinitrilen 16, wenn mit dem Molverhaltnis 1:1 gearbeitet wird. Umsetzung mit dem Molverhaltnis 2:1 liefert die Kondensationsprodukte 18. Orthoamides, XLII. — Reactions of Dinitriles with Orthoamide Derivatives of Formic and Carbonic Acid Succinodinitrile (5a) reacts with the orthocarbonic acid derivative 1a to give the guanidinium salt 6. Glutarodinitrile (5b) on reaction with 1a yields the benzonitrile 9. In the reaction of adipodinitrile (5c) and pimelodinitrile (5d) with 1a the ene-guanidino nitriles 10a and b, respectively, are produced. The higher homologous dinitriles 5e – h condense with 1a to give the ketene aminals 11a – d. The ene-guanidino nitriles 10 are transformed by alkylating reagents into guanidinium salts 13. Enamino nitriles 16 are obtained by reaction of the dinitriles 5 with orthoformic acid derivatives 3 in a molar ratio of 1:1. With excess orthoformic acid derivatives 3 (molar ratio 2:1) the dinitriles 5 condense to afford the compounds 18.

Die Reaktivitat der Orthocarbonate 4 und der Nitrile 1 wird verglichen. Carbonsauren werden durch 4b verestert. Durch Umesterung werden aus 4b die Orthocarbonate 4c-f und 9b gewonnen. Gemischt substituierte Orthocarbonate 8c-f sind aus den Nitrilen 1a, b zuganglich. Die Nitrile 2a und 3a setzen sich mit Alkalialkoholat in Alkohol zu den Orthocarbamidsaureestern 13a, b um. Spirocyclische Orthocarbonate 17a-d werden aus 4b und 1,2- bzw. 1,3-Diolen hergestellt. Phenol reagiert mit 1b zum gemischt substituierten Orthocarbonat 18a. Brenzkatechin setzt sich mit 1a zum Orthocarbonat 20a um. Das Verhalten von 4b gegenuber Aminen und Aminderivaten wird untersucht. Dabei werden u. a. Guanidine 21, Imidokohlensaureester 22a-c, 30, Carbamidsaureester 25, Harnstoffe 26, sowie das Isoharnstoffderivat 29 und das 1,3,4-Oxadiazol 31 dargestellt. Der Mechanismus dieser Reaktionen wird erortert. Aus 1b und Aminen oder Aminderivaten werden Imidokohlensaureester 22d-f, 38, N-Cyancarbamidsaureester 39 und Isoharn-stoffe 37 gewonnen. Sowohl aus 2a als auch aus 13b und Cyanamid entsteht der N-Cyanisoharnstoff 40. Bei hoheren Temperaturen reagieren die Nitrile 1a, b mit sekundaren Aminen zu Harnstoffen 26. In Ether reagiert 1b mit Pyrrolidin zum Guanidiniumsalz 41a, wogegen aus 1a und Pyrrolidin das Amidin 42 gebildet wird. o-Aminophenol, o-Phenylendiamin und Anthranil-saure werden mit 4b oder 1b in die Heterocyclen 43-45 ubergefuhrt. α- und β-Aminosauren reagieren mit 4b oder 1b zu den N-(Ethoxycarbonyl)aminosaureestern 46 bzw. 47. Orthoamides, XXXVIII1). — Contributions to the Chemistry of Orthocarbonic Acid Esters and α,α,α-Trialkoxyacetonitriles The reactivity of the orthocarbonates 4 and the nitriles 1 has been investigated. Carboxylic acids are esterified by 4b. Orthocarbonates 4c-f and 9b are prepared by transesterification of 4b. Mixed substituted orthocarbonates 8c-f are obtained from the nitriles 1a, b. The nitriles 2a and 3a react with alkali alcoholate in alcohol to yield the orthocarbamic acid esters 13a, b. Spirocyclic orthocarbonates 17a-d are prepared from 4b and 1,2 or 1,3-dioles, respectively. The reaction of phenol with 1b affords the mixed substituted orthocarbonate 18a. Catechol is converted by 1a into the orthocarbonate 20a. Reactions of 4b with amines and amine derivatives are studied. In the course of these investigations guanidines 21, imidocarbonic acid esters 22a-c, 30, carbamic acid esters 25, ureas 26, the isourea derivative 29, as well as the 1,3,4-oxadiazole 31 are prepared. The mechanism of these reactions is discussed. Imidocarbonic acid esters 22d-f, 38, N-cyano-carbamates 39, and isoureas 37 can be prepared from 1b and amines or amine derivatives. 2a as well as 13b react with cyanamide to give the N-cyanoisourea 40. Ureas 26 are formed in the reaction of la, b with secondary amines at elevated temperatures. The guanidinium cyanide 41a can be obtained by reaction of pyrrolidine with 1b in ether, whereas under similiar conditions from 1a and pyrrolidine the amidine 42 is produced. o-Aminophenol, o-phenylenediamine and anthranilic acid are cyclized by 4b or lb to afford the heterocyclic compounds 43–45. α- and β-amino acids are transformed by 4b or 1b into the N-(ethoxycarbony1)amino acid esters 46 and 47, respectively.

Nach der Umsetzung 1,3-disubstituierter 2,2-Dichlor-4,5-imidazolidindione (2) mit sek. Aminen lassen sich die Orthokohlensaurederivate 4, die unsymmetrischen Harnstoffe 5 und Oxamide 6 oder alle drei Verbindungen nebeneinander nachweisen. Das ausschliesliche Auftreten dieser Produkte bzw. ihr Mengenverhaltins zueinander hangt von der Art der Substituenten an den Stickstoffatomen des Imidazolidins und der Basizitat der eingesetzten Amine ab. Reaction of 1,3-Disubstituted 2,2-Dichlor-4,5-imidazolidindiones with sec. Amines The reaction of 1,3-disubstituted 2,2-dichloro-4,5-imidazolidindiones (2) with sec. amines yields the orthocarbonic acid derivatives 4, the unsymmetrical ureas 5 and oxamides 6, or all three compounds together. The nature of the products and the proportion in which they are formed depend on the nature of the substituents at the nitrogen atoms of the imidazolidine and one the basicity of the amines used in the reaction.

Publisher Summary This chapter discusses carbonic acid and its derivatives, a large and diverse group of compounds. Metacarbonic acid and its esters, such as carbon dioxide, esters of carbonic acid, anhydrides of primary esters of carbonic acid, mixed anhydrides of primary carbonates, and mono-carboxylic acids are also profiled with detailed information on general methods of preparation, properties, and typical reactions. Halides of carbonic acid, sulfur analogues of carbonic acid, and their derivatives, such as carbon oxysulfide and carbon disulfide, thiocarbonic acids and their halides, such as thiophosgene, amides, and related derivatives of carbonic acid, and the thiocarbonic acids are illustrated in a systematic manner. Special stress is evident in the discussion on urea and its derivatives, such as halogenoureas, ureides, and so on because of its commercial relevance as a fertilizer. Derivatives of iminodicarboxylic acid, such as biuret and nitrilotricarboxylic acid, sulfur analogues of carbamic acid, and hydrazino, azo, and azido derivatives of thiocarbonic acid are also emphasized in this chapter. Sulfur compounds of cyanogens, such as thiocyanic acid, cyanamide and its derivatives, and derivatives of carbodi-imide and orthocarbonic acid are also covered.