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A significant temperature effect on the new photochemical reactions of 9-α-bromopropionylanthracene has been noted. In comparison to the temperature effect on the fluorescence intensity of 9-propionylanthracene, it was suggested that the rotation of the carbonyl group on photo-excitation might operate as an enhancing factor in the intersystem crossing process.

The reaction of nitrile oxides with tropone yields a mixture of at least 8 products, the structures of which are based on spectral and chemical evidence. Both addition of the 1,3-dipole to the carbonyl group and cycloadditions to the CC double bonds system have been observed. Peri-, regio- and stereo-selectivity of the 1,3-dipole cycloaddition are discussed and rationalized on the basis of simple perturbation theory approach.

A number of 2-substituted quinoline-5,6-quinones were synthesized by oxidative animation of 2-substituted 6-hydroxyquinolines. 2-Chloroquinolinequinones, in which the halogen is activated owing to the joint effect of the carbonyl group and the heteroatom, were obtained from 2-chloro-4-methyl-6-hydroxyquinoline.

An X-ray diffraction study of 2(eq),4(ax),6(eq)-trichlorocyclohexanone, cis-2,6-dichloro- and gem-2,2-dichloro-4-tert-butylcyclohexanones shows the existence of a chair form in the solid state. Analysis of the experimental data shows: - an appreciable contraction of the endocyclic angle at the foot of the carbonyl group in the three molecules; - a strong overlap of the electronic clouds of the oxygen atom and the equatorial chlorine atoms in the α position with respect to the CO bond; - a considerable variation of the dihedral angle formed by the OC 1 C 2 and the C 1 C 2 X eq or C 1 C 2 H eq planes in the different molecules; - a negative or positive effect on ring planarity depending on the nature and position of the substituents.

The polycondensation of p -ferrocenylacetophenone in the presence of some metallic salts has been studied, and a scale of the catalytic activity of the metallic salts has been determined. The influence of the ferrocenyl residue on the carbonyl group in p -ferrocenylacetophenone and on the electrophysical properties is considered by applying Huckel MO calculations. The monomers synthesised show semiconducting properties.

The results of the oxidation of a number of 4-substituted 1,2-dimethyldecahydro-4-quinolones with hydrogen peroxide in methanol are in conformity with the results obtained by us earlier and confirm that the stereochemistry of the oxidation of nitrogen depends on the configuration of the methyl substituent in the 2 position of the decahydroquinoline ring. Under these conditions, the epimeric 1,2-dimethyl-trans-decahydro-4-quinolones undergo partial interisomerization at the 2 position to give a mixture of three N-oxides that correspond to both amino ketones. The oxidation of the corresponding ketals proceeds like the oxidation of amino alcohols without epimerization. It is thereby shown that the epimerization of the C2 center during the formation of the N-oxides from epimeric 1,2-dimethyl-trans-decahydro-4-quinolones occurs with the participation of the carbonyl group.

Various N-methylnitrones of sugars having a free carbonyl group were prepared by treatment with N-methylhydroxylamine. In each case, only one geometric isomer was obtained, to which the anti (Z) configuration is ascribed on the basis of the n.m.r. spectra, in particular of those obtained in the presence of an europium complex.

Homoadamantan-1-ol (14) wurde ausgehend von 5-Hydroxy-2-adamantanon (13) durch Ringerweiterung mit Diazomethan und Entfernung der Carbonylgruppe auf eindeutige Weise dargestellt. Die Struktur der Homoadamantan-1- carbonsaure (5), die aus 1 unter Koch-Haaf-Bedingungen nach langer Reaktionszeit erhalten wurde, konnte durch Abbau zum gleichen Alkohol 14 bestatigt werden. 13C-NMR-Spektren unterstutzen die Struktur zuordnung der 1- und 3-Homoadamantane. Das 3-Homoadamantyl-Kation (16) ist stabiler als das 1-Kation 17, aber Substitutenten sind in der 1-Position wegen differentieller sterischer Effekte der benachbarten Methylengruppen stabiler als in der 3-Position. Dies wird durch Computerrechnungen verschiedener Konformationen bestatigt. Bridgehead Homoadamantane Derivatives. Structural Evidence Homoadamantan-1-ol (14) was synthesized unambiguously from 5-hydroxy-2-adamantanone (13) by diazomethane ring enlargement followed by removal of the carbonyl group. The structure of homoadamantane-1-carboxylic acid (5), obtained from 1 under Koch-Haaf conditions and long reaction times, was confirmed by degradation to the same alcohol, 14. 13C.n.m.r. spectra provide further support for 1- and 3-homoadamantane structural assignments. The 3-homoadamantyl cation (16) is more stable than the 1-cation 17, but substituents are more stable at the 1- rather than at the 3-position due to differential steric effects of the adjacent methylene groups. Computer conformational analysis calculations confirm this conclusion.

The structure of the title compound was determined from three-dimensional X-ray diffractometer data. The compound crystallizes in space group Pbca with Z = 8 and cell dimensions: a = 19.92 A, b = 25.96 A, c = 15.82 A. The structural analysis, based on 2541 independent reflections, has converged to a final R 1 of 0.062. The structure consists of a trinuclear non-closed rhodium—iron complex with μ-diphenylphosphido and carbonyl groups bridging the rhodium and iron atoms. The RhFe distances are 2.659(2) and 2.674(1) A. Each iron atom is additionally bonded to a methylcyclopentadienyl group and a terminal carbonyl group. The closed structure (2RhFe)(FeFe), predicted on the basis of the “18 electron rule” and observed in related molecules, is suggested as being unstable with respect to the open structure as a result of the substitution of carbonyl ligands by the highly basic μ-phosphido groups.

1. The acid chlorides of carboxylic acids and trialkylsilyl chlorides add easily to the carbonyl group of fluoroketones in the presence of catalytic amounts of pyridine to give the esters (ethers) of α-chloro-substituted alcohols. The similar reaction with a trialkylsilyl azide is also accomplished in the absence of pyridine. 2. Cyanogen chloride in the presence of pyridine enters into the cycloaddition reaction with two moles of the fluoroketone to give the substituted 1,3,5-dioxazine derivative.

Semidione RC˙(OMMe3)–COR, M = C, Si, Sn, R = Ph, Me, entstehen aus Radikalen MMe3˙ und Benzil bzw. Biacetyl. M = Sn bedingt Pentakoordination mit der zweiten Carbonylgruppe und damit die cis-Strukturen 2c bzw. 4. 2c reagiert mit weiterem Me3Sn˙ einheitlich zum cis-Bis(stannyloxy)stilben 7. Mit M = Si liegt dagegen die trans-Form 11 vor, weiters Me3Si˙ fuhrt ausschlieslich zum trans-Bis(silyloxy)stilben 10. Analog bildet 1,3-Diphenylpropantrion mit Me3Sn˙ nicht das Semitrion-Anion-Radikal 16 oder den Sechsring 14, sondern das Sn-haltige Funfring-Semidion 15. ESR-Daten der beschriebenen Radikale werden angegeben. Formation and Reactions of O-Stannyl and O-Silylsemidiones Semidiones RĊ(OMMe3)–COR, M = C, Si, Sn, R = Ph, Me, are formed from radicals MMe3˙ and benzil or biacetyl, respectively. M = Sn produces, by pentacoordination with the second carbonyl group, the cis-structures 2c or 4, respectively. 2c reacts with additional Me3Sn˙ uniformly to the cis-bis(stannyloxy)stilbene 7. With M = Si, however, the trans-structure 11 is preferred. Further reaction with SiMe3˙ gives only the trans- bis(silyloxy)-stilbene 10. Starting from 1,3-diphenylpropanetrione and Me3Sn˙, we observed neither the semitrione anion-radical 16 nor the six-membered ring 14, but the Sn-containing five-membered semidione 15. E.s.r. data of the described radicals are given.

Reduction of methyl 4,6-O-benzylidene-α- and β-d-glycopyranosidulose derivatives with sodium borohydride was carried out. From the yield of the axial and equatorial epimers, a possible mechanism of the borohydride reduction and factors determining the directions of the reagent’s attack to a carbonyl group are discussed.

An annelated[13]annulenone (3) was prepared starting from o-ethynylbenzaldehyde 1 in order to examine the effect of annelation on the ring current of the inner thirteen membered ring. It was found that two benzene rings reduce a paramagnetic ring current arising from polarization of a carbonyl group in the inner ring.

Prenyllithium (3-methylbut-2-enyl-lithium) (1) and cis-crotyllithium (Z-but-2-enyl-lithium) (2) in tetrahydrofuran solution, prepared according to the method of Eisch & Jacobs, react with carbonyl compounds to give the branched alcoholates with moderate to high selectivity, unless access to the carbonyl group is strongly hindered (see the Table). Adamantanethione (12) reacts with 1 to give the unbranched thiolate.

In the presence of magnesium and in hexamethylphosphoric triamide (HMPT), trimethylchlorosilane reacts with α,β-acetylenic ketones to give in most cases 1,4 addition of two trimethylsilyl groups to the conjugated system: allenoxysilanes, which constitute a new class of organometallic compounds, are formed. These upon hydrolysis give the corresponding silylated α,β-ethylenic ketones. Other reactions also take place: complete reduction of the carbonyl group giving polysilylated allenes; reductive duplication accompanied by O-silylation, and enolization. α,β-Acetylenic aldehydes give the same type of reactions.

Wir fanden, das sich vinylsubstituierte Δ3-Pyrrolin-2-one leicht bilden, wenn die Vinylgruppe in lineare Konjugation zur Carbonylgruppe zu stehen kommt. Diese Pyrrolinone zeigen ein Absorptionsmaximum bei 235 –245 nm. – Der vinylsubstituierte Urobilinester 26 ist so unbestandig, das eine ausreichende Charakterisierung nicht moglich war. Syntheses of Bile Pigments, VI1). – Synthesis of Vinyl Substituted Pyrrolinone Derivatives We have found that vinyl substituted Δ3-pyrrolin-2-ones are easily formed when the vinyl group and carbonyl group are linearly conjugated. Pyrrolinones of this type show an absorption maximum at 235–245 nm. – The vinyl substituted urobilin ester 26 was too unstable to permit full characterization.

2-Azidopyrido[1,2-a]pyrimidin-4-one can exit only in the azido form and undergoes cyclo-addition reaction with 1,3-dicarbonyl compounds to form 1,2,3-triazole derivatives. Under the influence of bases or hydrochloric acid the carbonyl group is attacked with subsequent opening of the pyrimidine ring. This causes an immediate cyclization of the azide group to give a tetrazolo derivative. In a similar way a triazole ring can be formed from the appropriate hydrazino derivatives of pyrido[1,2-a]pyrimidin-4-one.

The reactions of MexMCl5-x (M = Nb, Ta, x = 1, 2) with a variety of ketones have been investigated. Bulky ketones give complexes of the type MexMCl5-x· RR′CO for R = R′ = cyclohexyl; R = Me, R′ = t-Bu; R = Me, R′ = neopentyl. Addition of the methylmetal group to the carbonyl group takes place with less bulky ketones and benzaldehyde. Reactions with oxygen and γ-picoline-N-oxide have also been investigated.

The conformational dependence of vicinal 15N-C-C-H coupling in N-methylacetamide as a model compound for coupling in the peptide backbone is investigated by means of the self-consistent perturbation formulation for coupling constants in the INDO approximation of self-consistent-field molecular orbital theory. Because the calculated coupling constants cover a range of at least 7 Hz, they should be useful in determining the ψ angles in peptides. The prediction of opposite signs for gauche and trans coupling indicates the need for sign determination. Non-negligible coupling constants of positive sign for the gauche arrangements are undoubtedly due to a substituent effect involving the lone pair electrons on the nitrogen and the π-electrons of the carbonyl group. Calculated results are compared with the available experimental data.

Dielectric measurements of samples of poly(β-benzyl-L-aspartate) in the α and ω forms were performed over the frequency range from 30 Hz to 1 MHz and at temperatures from −40 to 140°C. A dispersion peak arising from the molecular motion of the side chain was found and is discussed in detail. The activation energies estimated from the Arrhenius plot were very similar for the α form and the ω form. The Cole—Cole plot showed that (e0−e∞) of the α form is almost equal to that of the ω form or is a little larger. But the dispersion temperature of the α form is higher than that of the α form. On the basis of our experimental results, the motion of the carbonyl group in the side chain was discussed in relation to the interaction between the main chain and the side chain.

It it shown that the photo-oxidation of aromatic molecules containing an active methylene group can be used to introduce isotopic oxygen. Photo-oxidation of xanthene results in the formation of xanthone with the oxygen label appearing in the product at the carbonyl group. In this way, 100% enrichment can be realized. A brief discussion of other systems to which this method may be extended is also given.

Ethyl 2-thioxo cycloalkanecarboxylates of ring sizes 5–9 exist in CCl 4 solution in the tautomeric cis -enethiol form, whereas the 10–12 membered ring compounds exist as an equilibrium mixture of several tautomeric forms. On the basis of NMR and IR spectral data it is concluded that the cis -enethiols exist as equilibrium mixtures of two rapidly interconverting rotameric forms, one involving intramolecular H-bonding, the other having the ester group rotated through 180° so that the ester carbonyl group is unable to form an intramolecular H-bond, although still conjugated with the enethiolic double bond. The relative equilibrium concentrations at ∼35° of the two rotameric cis -enethiol forms have been determined for all investigated compounds.

The concentration profile of a deterrent (di-n-butyl phthalate) which had been diffused into a nitrocellulose sphere (ball propellant) containing nitroglycerin was studied by means of autoradiography. Results indicate a level concentration part way into the sphere with an abrupt dropoff in concentration. An explanation for this type of concentration profile is offered based on hydrogen bonding of the deterrent carbonyl group with unesterified hydroxyl groups in nitrocellulose.

N,N,N-Triethyl-N-[β-formyl-vinyl]-ammoniumperchlorat (1), a cationic α, β unsaturated aldehyde reacts with water at the carbonyl group. No addition was found to the olefinic double bound. This unusual behavior will be explained. The temperature dependence of the equilibrium constant measured by 1H NMR spectroscopy result in ΔH = —3.8 ± 0.5 kcal/Mol, ΔS30 °C = —20 ± 3 e. u.

A topological approach to the LIS simulation process of compounds bearing the carbonyl functional group is reported. The Lanthanide was always found to complex in the less hindered position, along the sp 2 lone-pair orbital of the O atom. The relevance to chemistry of such an approach is that only chemical significant positions are considered as feasible sites of complexation of the Lanthanide with the substrate, disregarding all other positions. More important, the results obtained have thrown some light on the factors that may influence the equilibria of conformationally mobile systems, in the presence of LSR. The reliability of the method employed has been tested in several disparate carbonyl derivatives.

By reaction of octaethylporphine [(OEP)H2] with osmium tetroxide in diethyleneglycil monomethyl ether at temperatures about 200°C, new octaethylporphinatoosmium (II) carbonyl complexes of the type (OEP)Os(CO)X are obtained in good yield after addition of a Lewis base X[where X = MeOH, EtOH, THF, C5H5N, PPh3, and AsPh3]. Treatment of these complexes with P(OMe)3 yields (OEP)Os[P(OMe)3]2, both axial ligands (CO and X) being replaced. All compounds are fully characterized by elemental analyses, electronic absorption, IR, NMR and mass spectra. The ligand X exerts a trans-effect on the carbonyl group: as the back-bonding capacity of X increases the carbonyl stretching frequency rises, indicating diminishing back bonding to the CO group. IR data show that back bonding onto the CO-ligand increases in the porphinatometal carbonyls (P)M(CO)X for different metals M in the order Fe

Infrared spectra of new iron(III) complexes with urea derivatives: [Fe (CH3HNCONH2)6]X3; [Fe(C2H5HNCONH2)6]X3 and [Fe(CH3-HNCONHCH3)6]X3 (where X = Cl−, NO−3 or 1 2 SO2−4) have been recorded and their interpretation given. The analysis of the infrared spectra was based on a comparison of the positions of bands corresponding to the vibrations of characteristic groups appearing in the complexes and the free ligands. Comparison and analysis of the data show that the urea derivatives coordinate with mono- and disubstituted iron(III) through the oxygen atom of the carbonyl group.

Evidence presented indicates that the functional groupings of cucurbitacin E (α-elaterin) are as follows: an αβ-unsaturated ketone, a 1:2-diketone (enolised), three hydroxyl groups, one of which is acetylated, and probably a further carbonyl group.

The 14N chemical shifts in a series of primary and secondary amides have been obtained from the proton spectra by double irradiation techniques. The 14N shifts in the primary amides are affected only slightly by changes in the substituent on the carbonyl group, but a wider range is found for secondary amides. A qualitative explanation of the observed shift changes is put forward in terms of the effect that the various substituents, have upon the nitrogen lone pair of electrons.

The discovery that the (benzylthio)carbonyl group is stable in concentrated hydrochloric acid has permitted the removal in that medium of isopropylidene blocking groups from 3-O-[(benzylthio)carbonyl]-1,2;5,6-di-O-isopropylidene-α-D-glucofuranose to furnish crystalline 3-O-[(benzylthio)carbonyl]-β-D-glucopyranose. Benzoylation of the latter provided a derivative which has made possible the synthesis of methyl 2,4,6-tri-O-benzoyl-α and β-D-glucopyranosides.

The transitions between electronic levels of polyatomic molecules and their relationship to the photochemistry of such molecules are considered. These transitions often occur without emission or absorption of radiation so that the state first formed by the absorption of radiation may not be the one most concerned with the resulting reaction kinetics. The present discussion reviews the data for a few polyatomic molecules, i.e., ketene, acetone, biacetyl, benzene, and ketones with C atoms to the carbonyl group, to determine both the extent of and the character of intersystem cross-overs and of internal conversions. The terms internal conversion and intersystem cross-over refer to a nonradiative transition between states of the same multiplicity and of different multiplicity, respectively. The scope of the subject is limited to the gas phase. (Author)

To obtain information on the electronic structure of hydrazylic free radicals, the electron spin resonance hyperfine structure of a group of such radicals derived from 1-1-diphenyl-2-benzoyl-hydrazyl has been investigated as a function of suitable substitutions of atoms or groups at different positions in the benzoylic ring. It has been found that the introduction of a nitric group at an « ortho » position to the carbonyl group causes a change of the spectrum which, on the contrary, is not observed if the same group is introduced at a « para » position. This indicates a considerably largerI · S interaction in the former case, as compared with the latter, namely a charge transfer preferentially centered on the ortho positions.

There are two methods for the determination of carbonyl group in cellulose by means of reduction with NaBH4. One is the gasometric method proposed by Lindberg et al., and another is the volumetric method proposed by Lyttle et al. The former involves some troubles in its analytical operation. Therefore the authors adopted the latter, and carried out some experiments in order to check up the method.An analytical method now established is as follows. After a sample containing carbonyl group, such as D-glucose or oxydized cellulose by HIO4, is immersed in 0.010.13 M NaBH4 (pH 12.012.3) for 2448 hrs at room temperature and then filtered, a 0.040.4 N KIO3 solution and a 0.5 N NaOH solution are added to the filtrate successively. The amounts of consumed NaBH4 are calculated from the amounts of consumed KIO3 estimated by a titration With a 0.1 N Na2S2O3 solution in acidic condition.At a range of pH 12.012.3, 57% of the amount of consumed NaBH4 are effective for the reduction of carbonyl group in the sample. This is confirmed by the amounts of non-reacting hydrogen gas estimated with a gas burett.The results of treatment of D-glucuronolaeton and the oxydized cellulose by NaBH4 at pH 12.012.3 show that the carboxyl group and its lacton are resistant to the reduction.

To obtain ultraviolet stabilizing polymers, 2-hydroxy-4-acryloyloxybenzophenone was prepared from 2,4-dihydroxybenzophenone and copolymerized with styrene. Copolymers containing three different amounts of ultraviolet absorber were prepared. These copolymers, unstabilized pure polystyrene and a series of stabilized polystyrene, were exposed to ultraviolet, and the ultraviolet stability of these polymers was compared by the relative amount of infrared absorption around 1700 cm−1 due to the carbonyl group. Ultraviolet stability of the copolymers is very similar to that of blend polymers and is higher than that of unstabilized pure polystyrene.

Oxidation of cyclic hydroxamic acids (1-hydroxy-2-indolinone, II, 4-hydroxy2H-1,4-benzoxazin-3(4H)-one, V, and their derivatives with a gem-dimethyl group adjacent to the carbonyl group) affords nitroxides III, III-Me2, VI and IX, whose ESR spectra are presented and discussed. On recrystallization of the hydroxamic acids from D2O, only II exchanges the methylene protons, assisting in the interpretation of the ESR spectrum of III.

Dibenzoyldisulfide (DBDS) reacted exothermically with phosphorus triamide P (NR2) 3 in benzene to yield a corresponding benzamide.Although dibenzoylsulfide (DBS) was considered as an intermediate, DBS was not obtained. The yield of the corresponding benzamide decreased with increase of the bulk of the alkyl group on the nitrogen atom of P (NR2) 3.In the reaction with P (OEt) 3, DBS was obtained in good yield in the reaction of molar ratio 1 : 1. This is in contrast with the case of P (NR2) 3. Excess P (OEt) 3 was allowed to react with DBDS to yield equivalent ethyl benzoate and ethyl thiobenzoate.In the reaction of DBS with P (NR2) 3, it is considered that the nitrogen atom of P (NR2) 3 attacks the carbon atom of the carbonyl group and then a tervalent phosphorus compound such as acylthiophosphite is formed. In the case of P (OFt) 3, the phosohorus atom is considered to attack the carbon atom of the carbonyl group and to give acylphosphonate and acylthiophosphite.

Information pertaining to the position of the carbonyl group relative to the nitrogen atom and to the size of one of the nitrogen rings in lycopodine has been obtained through a study of the reactions of α- and β-cyanobromolycopodine.

Esters and methyl derivatives of a new pigment pyoluteorin, produced by a strain of Pseudomonas aeruginosa have been synthesized, and catalytic hydrogenation of the derivatives was carried out to give the corresponding dechloro compounds. It has become clear that pyoluteorin is composed of an unsaturated nucleus and has two phenolic hydroxyls, one amino and the other a cross-conjugated carbonyl group.

Irradiation of polyphenylvinylketone with 3650 A ultra-violet light in the solid state or in benzene solution brings about a decrease of the molecular weight. In the presence of isopropanol no photoreduction is observed and naphthalene is not an inhibitor of the photodegradation. These results and the analysis by vapour phase chromatography of volatile products formed suggest that the principal mechanism is the abstraction of a hydrogen in position γ to the carbonyl group followed by breaking of the main polymer chain (Norrish type II mechanism).

The proton NMR spectra of a series of 2-benzal-, 2-benzyl-, and 2-benzyl-2-bromo-indanones and a series of substituted 4,4-dimethyltetralones have been determined. The cis and trans isomers of 2-benzalindanones are easily identified through analysis of their PMR spectra. Peculiarities in the complex spectra of 2-benzyl and 2-benzyl-2-bromoindanones and tetralones are partially accounted for on the basis of conformational preference about the carbon-carbon bond attaching the 2-benzyl moiety to the 2-position of the indanone and tetralone rings. An internal complexation between the benzyl phenyl and the carbonyl group may be involved in some of these structures. The 4,4-dimethyltetralones exhibited two methyl resonances as a result of substitution in the 2-position and the stereo-structures are discussed in terms of conformational analysis.

In 1-Phenylazo-2-naphthol und in 2-Phenylazo-1-naphthol liegt die Karbonylvalenzschwingung der Hydrazonform (Ih bzw. II in Abb. 1) bei 1570 cm−1 und nicht, wie bisher angenommen wurde, bei 1625 cm−1. Wegen des hohen Anteils der Grenzstrukturen vom Typ Ih an der Elektronenstruktur der Hydrazonform ist der Doppelbindungscharakter der Karbonylgruppe (etwa auf 2/3) stark erniedrigt. Bei den beiden intensiven Banden bei 1625 und 1600 cm−1 handelt es sich um Ringschwingungen. Dies ist auch beim 2-Hydroxy-1-naphthaldehydanil (V) der Fall, dessen C=N-Valenzschwingung bei 1570 cm−1 liegt, wie mit Hilfe der 15N-Substitution gezeigt wird. Der Nachweis der Karbonylvalenzschwingung ist der erste unmittelbare Beweis dafur, das es sich bei der langerwellig absorbierenden Form des im UV-Absorptionsspektrum beobachteten losungsmittelabhangigen Gleichgewichtes tatsachlich um die Hydrazonform handelt. Bei 3-Phenylazo-2-naphthol (III) liegt das Gleichgewicht stark auf der Seite der Azoform, was auch aus der geringen Neigung zum Sauerstoffaustausch mit D218O hervorgeht. In 1-phenylazo-2-naphthol and 2-phenylazo-1-naphthol the carbonyl valency vibration of the hydrazone form (Ih, II in Fig. 1) occurs at 1570 cm−1 and not at 1625 cm−1 as has hitherto been assumed. Because of the high contribution of structures of the type Ih' to the electronic structure of the hydrazone form the double-bond character of the carbonyl group is strongly reduced (to ca. 2/3). The two intense bands at 1625 and 1600 cm−1 are ring vibrations. This also applies to 2-hydroxy-I-naphthaldehyde anil (V) for which CN-valency vibration occurs at 1570 cm−1, as is shown with the help of 15N-substitution. The detection of a carbonyl valency vibration is the first direct evidence that the hydrazone form is the species absorbing at longer U. V. wavelengths involved in the solvent-dependent equilibrium. In 3-phenylazo-2-naphthol (111) the equilibrium lies strongly on the side of the azo form, as can also be deduced from the low tendency to oxygen exchange with D218O.

The structure and absolute stereochemistry of fauronyl acetate and cryptofauronol have been elucidated as formulae I and II, respectively, by the following series of reactions coupled with spectral determinations. Fauronyl acetate (I) and cryptofauronol (II) were interconverted by hydrolysis and acetylation. Fauronyl acetate was transformed to the ketone (VIII), in which the environment of the carbonyl group was established, and to valeranone whose absolute stereostructure (XIV) is known.

1. It has been shown that O,O-diethyl hydrogen phosphorothioitein presence of sodium ethoxide reacts readily at the double bond of unsaturated ketones with formation of keto phosphonothionic esters. It adds to saturated ketones at, the carbonyl group with formation of α -hydroxy phosphonothionic esters. 2. O,O-Diethyl hydrogen phosphorothiotte -adds at the carbonyl group of unsaturated and saturated aldehydes with formation, respectively, of unsaturated and saturated α-hydroxy phosphonothionic esters. 3. A method .has been developed for the synthesis of keto phosphonothionic esters and of unsaturated and saturated α-hydroxy phosphonothionic esters.