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The addition of the chiral nucleophiles Na-2 and Li-5 to pyridinium compounds 1 and the subsequent ring closure (Pictet-Spengler cyclization) to indoloquinolizines 3a and 7b, respectively, proceed stereoselectively (d.e. for 3a: 54%; for 7b: ≥95%). Proof for the absolute configuration of these products is provided by their CD spectral data and the transformation of 7b into the indole alkaloids (+)-vallesiachotamine [(Z)-6] and (-)-isovallesiachotamine [(E)-6].

From thirty three new optically active 1,5-benzodiazepine derivatives the UV and CD data are reported and the bands discussed related to corresponding electronic transitions respectively stereochemical features.

From forty one chiral benzodiazepin-2-ones the UV and CD data are reported and the bands discussed with respect to corresponding electronic transitions respectively stereochemical features.

The reaction between 2-phenylthiobenzhydrazide and aldoses has been investigated; the products obtained in these reactions have the structure of 2-polyhydroxyalkyl-Δ4-1,3,4-thiadiazolines as shown by spectroscopic evidence and by single crystal X-ray analysis

A route to optically active variously substituted 4-methyl- and 4-methyl-7-substituted 1,3,4,5-tetrahydro-2H-1,5-benzo-diazepin-2-ones as analogues of commercially available Lofendazam (7-chloro-5-phenyl-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one, 1) was developed. Fortyone variously substituted optically active compounds having the same configuration were prepared and the UV and CD spectra of the parent compounds bearing no additional substitution in the benzene ring are discussed.

Syntheses of 5α-cholesteno[3,2-d]- (5a), [2,3-d]- (12a), and [3,4-d]pyrimidines (15a) have been achieved by using hydroxymethylene derivatives of relevant cholestanones prepared from cholesterol (1). Their CD spectra exhibit at least three Cotton effects between 300 to 200 nm, a first CD band around 290, a second one around 260 and a third one around 220 nm. A quadrant rule is developed and applied to the determination of the sign of the first CD band, while a helicity rule is applicable to the third CD band. The first band is positive in the [3,2-d] series, whereas it is negative in the [2,3-d] and the [3,4-d] series. The third band is negative in all three series.

The correlation between the absolute configuration and CD of aza- and thiaflavanone (1, 2) is discussed: the 2R configuration for the laevorotatory enantiomers has been established by a comparison of their CD data with those of (S)-(−)-3. For the Cotton effect within the n π* band of 1 and 2 the same helicity rule is valid as for the homochirally analogous flavanones (3). Starting from (S)-(−)-flavanone (3) and cholesterol (5), we have synthesized the chromane derivatives 4 and 20, respectively. The 1Lb band of the chromane chromophore has been unequivocally identified in the range between 255 and 290 nm in the CD spectra of 4 and 20. For this Cotton effect the opposite helicity rule is valid as compared with the homochirally analogous tetralins: the P/M helicity of the hetero ring leads to a negative/positive CD within the 1Lb band. The modification of the helicity rule can be explained with the help of Petruska's “q values”.

Synthesis of unsubstituted 5X'-cholesteno(3,2-d)- (5), (2,3-d)- (12), (3,4-d)(15) and 5.C- and 5 ~-cholest-3-eno(4,3-d)pyrimidines (21) and (21') has been achieved using hydroxymethylene derivatives of relevant cholestanones prepared from cholesterol(1). Their 2'-derivatives (5a - Se), (12a), (15a - 15c), (21a - 21c) and (21'a,21'b) could also be prepared. Attempts to prepare cholest-l-eno(l,2-d)pyrimdine system through 5X-cholestan-l-one(28) failed. 5 $-Cholest-6-eno(7,6-d)pyrimidine(33) was prepared by the reaction of cholestan-7-one with trisformylaminomethane. Three Cotton effects were observed between 350-200 nm in all these compounds intheir CD spectra. They have been assigned to n 3 K* and 7T -tT*transitions from long to short wave lengths. Quadrant rule has been applied for determining the sign of the first band CD, while helicity rule has been applied for the third band CD. Present work describes the synthesis of six series of optically active cholestenopyrimidines (Fig.l), e.g. 5 and its 2'-derivatives (5a-5e), 12 and its

Synthesis of Medium and Large Rings, XXXIII[1].–Optically Active 3a,6-Methanohydroazulenes via Chiral Induction of the Solid-State Photochemical Rearrangement of Bis(1,2:5,6-di-O-isopropylidene-α-D- and -α-L-glucofuranos-3-O-yl) 3,6-Hexanooxepine-4,5-dicarboxylate Irradiation of an aqueous suspension of the crystalline 3,6-hexanooxepine-4,5-dicarboxylic esters 2a and 2b affords the (3aS,6R,8aR)- and (3aR,6S,8aS)-methanohydroazulenes 3a and 4b in 54–58% yield with 92–93% de. Irradiation of an ethereal solution of 2a–2d on the other hand proceeds with low diastereoselectivity. The absolute configurations were established by X-ray structural analysis of the dimenthyl ester (+)-3d, comparison of CD spectra and chemical transformations. The origin of the high diastereoselectivity of the rearrangements 2a 3a and 2b 4b in the solid state is discussed on the basis of the X-ray structural analysis of the 3,6-heptanooxepine (–)-5a. Procedures for the removal of the chiral auxiliaries are described. Di-O-isopropylidene-α-L-glucofuranose is recycled in 95% yield.

Asymmetric reactions on chiral bis (diphenylphosphine) metal complexes having C2 symmetry axis of the chelate ring obey the simple stereochemical rules which establish a relationship between the product configuration and complex conformation. The stereochemical basis of the application of this rule has been studied on the example of the cross-coupling reaction of crotyl alcohol derivatives and arylmegnesiumbromides on trans-bis-1S,2S- and trans-bis-1R,2R- (diphenylphosphino)cyclopentanenickel dibromide (NiBr2 ((SS)-dpcp) and NiBr2 ((RR)-dpcp)). Monitoring the reaction mixture by circular dichroism and 31P NMR spectroscopy shows that this reaction goes through Ni(Ph)Br(dpcp), NiPh2(dpcp) and Ni0(dpcp) intermediates. 31P NMR spectroscopy, just as CD, did not reveal the π-allyl (Y)Ni(dpcp) species (Y = leaving group of the crotyls). Probably, they take part in the reaction at a very small concentration. The observed effect of the influence of Y volume on the enantiomeric excess value of the reation was explained on the assumption of an equilibrium between two forms: in the one, the Ni in Ni(Y) (dpcp) is coordinated to the crotyl function, and in the other, Y is covalently bonded to the crotyl, with the Ni π-bonded to the crotyl double bond. Exchange of phenyl for 1-naphthyl group in ArMgBr is accompanied by a decrease of ee from 58% to 0%. Loss of enantioselectivity can be explained by attack of the bulky nucleophile from outside but not within the inner sphere of the complex as in the case of Ph. Major and minor diastereomers (8:1) of π-allyl(1-Np)Ni((SS)-dpcp) are not intermediates of this reaction but deadlock substances.

Chiroptical properties of the title compounds have been studied. The influence of the substitution pattern of the aromatic moiety and the consequence of the amide → thioamide conversion are discussed as well.

Bidentate complexes of dimolybdenum tetraacetate with 1,3-diaxial diols show Cotton effects around 490–540 nm (CD band I), 400–440 nm (II), 350–380 nm (III), 320 nm (IV) and 280 nm (V). The sign of the Cotton effect II can be predicted by a proposed sector rule. It seems that from the Cotton effects for cyclic 1,3-diols the absolute configurations or conformations can be obtained.

3-Hexulose phosphate synthase catalyzes the aldol reactions between D-ribulose 5-phosphate 1 and a rather wide range of aldehydes. The stereoselectivity of the reaction was investigated with propionaldehyde 3 as substrate. The sense of chirality at carbon atom 5 is definite, but two isomers at carbon atom 6 are formed during formation of the new CC bond.

A synthetic way for obtaining 6-amino-2,4-dimethylquinoline derivatives from 2,5-dichloraniline by successive ring closure, nitration, aromatic substitution at so activated quinoline ring, followed by reduction of the nitro group to amino group and alkylation of the last is described.

The thermal decomposition of spiro-1-pyrazolines 2 obtained by the cycloaddition of exocyclic α,β-unsaturated ketones with diazomethane gives spirocyclopropanes 4 with high selectivity and the new β-methyl-3-benzylidene derivatives 3. The configuration and conformation of the thermolysis products 3 and 4 were elucidated by different n.m.r. methods.

Revision of previous work shows that PLE-cataiyzed hydrolysis of 1 leads to the (S)-alcohol 5 and not the (R)-alcohol 3 . However the homologue 2 gives the (R)-alcohol 4 .

Hydrolysis of 3β-5-diacetoxy-5β-cholestan-6-one oxime (1) gave seven products which, in addition to 3β-acetoxy- and (6E)-3β-hydroxy-5-methoxy-5α-cholestan-6-one oxime (3 and 4), are identified as the dimeric steroids (6E,6′E)-6-(6′-hydroxyimino-5′α-cholestan-5′-yl-oximino)cholestanes 6–10. On the other hand, the 3α epimer 3α,5-diacetoxy-5β-cholestan-6-one oxime (2) afforded the monomeric (6E)-3α-hydroxy-5-methoxy-5α-cholestan-6-one oxime (5) and (6E)-3α-hydroxy-4-cholesten-6-one oxime (11) only. All new compounds are characterized by NMR and MS methods. The CD spectra of 1–12 are documented.

Synthesis of unsubstituted 5X'-cholesteno(3,2-d)- (5), (2,3-d)- (12), (3,4-d)(15) and 5.C- and 5 ~-cholest-3-eno(4,3-d)pyrimidines (21) and (21') has been achieved using hydroxymethylene derivatives of relevant cholestanones prepared from cholesterol(1). Their 2'-derivatives (5a - Se), (12a), (15a - 15c), (21a - 21c) and (21'a,21'b) could also be prepared. Attempts to prepare cholest-l-eno(l,2-d)pyrimdine system through 5X-cholestan-l-one(28) failed. 5 $-Cholest-6-eno(7,6-d)pyrimidine(33) was prepared by the reaction of cholestan-7-one with trisformylaminomethane. Three Cotton effects were observed between 350-200 nm in all these compounds intheir CD spectra. They have been assigned to n 3 K* and 7T -tT*transitions from long to short wave lengths. Quadrant rule has been applied for determining the sign of the first band CD, while helicity rule has been applied for the third band CD. Present work describes the synthesis of six series of optically active cholestenopyrimidines (Fig.l), e.g. 5 and its 2'-derivatives (5a-5e), 12 and its

A route to optically active variously substituted 4-methyl- and 4-methyl-7-substituted 1,3,4,5-tetrahydro-2H-1,5-benzo-diazepin-2-ones as analogues of commercially available Lofendazam (7-chloro-5-phenyl-1,3,4,5-tetrahydro-2H-1,5-benzodiazepin-2-one, 1) was developed. Fortyone variously substituted optically active compounds having the same configuration were prepared and the UV and CD spectra of the parent compounds bearing no additional substitution in the benzene ring are discussed.

From forty one chiral benzodiazepin-2-ones the UV and CD data are reported and the bands discussed with respect to corresponding electronic transitions respectively stereochemical features.

2,3-Dihydro-2(R)-methyl-1,5-benzoxazepin-4(5H)-one [(R)-3] and its enantiomer (S)-3 have been synthesized via the optical resolution and subsequent chemical transformations of (±)-3-(2-nitrophenoxy)butyric acid (1). Compounds (R)-3 and (S)-3 were converted into optically active 1,5-benzoxazepines (R)-7–(R)-14 and (S)-15–(S)-32.

Hydrolysis of 3β-5-diacetoxy-5β-cholestan-6-one oxime (1) gave seven products which, in addition to 3β-acetoxy- and (6E)-3β-hydroxy-5-methoxy-5α-cholestan-6-one oxime (3 and 4), are identified as the dimeric steroids (6E,6′E)-6-(6′-hydroxyimino-5′α-cholestan-5′-yl-oximino)cholestanes 6–10. On the other hand, the 3α epimer 3α,5-diacetoxy-5β-cholestan-6-one oxime (2) afforded the monomeric (6E)-3α-hydroxy-5-methoxy-5α-cholestan-6-one oxime (5) and (6E)-3α-hydroxy-4-cholesten-6-one oxime (11) only. All new compounds are characterized by NMR and MS methods. The CD spectra of 1–12 are documented.

The thermal unfolding of cytochrome P-450 LIN and P-450 CAM measured in presence and absence of their specific substrates was analyzed by circular dichroism (CD) and the α-helix content was estimated. Both proteins show, independent of the presence or absence of the substrates, nearly the same amount of loss of the CD in the peptide region. The comparison of the half transition temperature determined from different chromophores and different methods indicates a non-two-state transition of the thermal unfolding. For such analysis we developed a new spectrometer, which is capable of measuring the CD simultaneously at all wavelengths in a limited wavelength region.

The thermal decomposition of spiro-1-pyrazolines 2 obtained by the cycloaddition of exocyclic α,β-unsaturated ketones with diazomethane gives spirocyclopropanes 4 with high selectivity and the new β-methyl-3-benzylidene derivatives 3. The configuration and conformation of the thermolysis products 3 and 4 were elucidated by different n.m.r. methods.

Starting from cholesterol the three possible stereoisomeric 1,4-benzodioxanes 24, 31, 32 and a series of analogues with 2βH,3βH configuration (25–27, 29, 30) have been synthesized. The α band of the 1,4-benzodioxane chrompohore has been unequivocally identified in the CD spectra between 325–300 nm. For its Cotton effect the same helicity rule is valid as for homochirally analogous tetralins: the P/M helicity of the heteroring leads to a positive/negative CD within the α-band. The (2′R,3′R) configuration of 6 has been established by a comparison of its CD data with those of 39 and with the help of the above-mentioned helicity rule. This allows the assignement of the (2S,2′R,3′R) configuration of (−)-silandrin (3).

3-Hexulose phosphate synthase catalyzes the aldol reactions between D-ribulose 5-phosphate 1 and a rather wide range of aldehydes. The stereoselectivity of the reaction was investigated with propionaldehyde 3 as substrate. The sense of chirality at carbon atom 5 is definite, but two isomers at carbon atom 6 are formed during formation of the new CC bond.

Revision of previous work shows that PLE-cataiyzed hydrolysis of 1 leads to the (S)-alcohol 5 and not the (R)-alcohol 3 . However the homologue 2 gives the (R)-alcohol 4 .

A synthetic way for obtaining 6-amino-2,4-dimethylquinoline derivatives from 2,5-dichloraniline by successive ring closure, nitration, aromatic substitution at so activated quinoline ring, followed by reduction of the nitro group to amino group and alkylation of the last is described.

The CD spectra Of some resorcylic acid macrocyclic lactones (RAL) are reported. The spectra Of the E,Z -isomeric ketones 1,6 are very similar in shape and magnitude. The Cotton effects Of the 7α-alcohols 2 and 7 are also Of the same shape, but the Δϵ values Of 7 are Only ca. 50% Of those Of the Others. The E-7β-Ol 3 gives a completely different CD, whereas in the Z-series 8 shows a similar CD curve as 6 and 7 , but with again reduced magnitude. The CDs Of the acetates 4 and 5 are very similar to those Of the corresponding alcohols 2 and 3 , resp. The effect Of the 7a- and 7β-hydroxy Or acetoxy group On the absolute conformation Of the “chain” from C(5) to C(10) is thus transmitted to the absolute value of the torsional angle Of the inherently chiral chromophore C(11)-C(12)-C(12a)-C(1a)-C(=0)O in 2,3 and 4,5 , resp. The CD spectra Of the E,Z -isomers do not exhibit straightforward correlation with the configuration around the C=C double bond.

Some oximes and oxime acetates of transoidal cholestenones have been synthesized. In three cases of stable syn/anti pairs of oximes both stereoisomers could be separated. The CD-spectra of all compounds have been measured. All syn-isomers show an additional CD band around 280 nm, which does not exist for anti-oximes.

The absolute configuration of the 2-(phenylmethyl) pyridine derivatives 1-9 had been established by X-ray diffraction and chemical correlation. Their CD spectra have been studied in different solvents for the free and protonated forms. It has now been found that, from the sign of the strong CD couplet between 270 and 220 nm, which was observable for all these compounds besides 7 and 9, their absolute configuration can be determined much quicker

The four possible diastereomeric 5,7-oxido-6-hydroxyiminocholestanes and their O-acetates have been synthesized. The stereochemistry of one of the latter has been proved unequivocally by x-ray diffraction. Their 1H and 13C NMR and also their circular dichroism spectra are discussed. It is now also possible to determine unequivocally the stereochemistry of the ring-junction geometry and the oxime E or Z stereochemistry.

Chiroptical properties of the title compounds have been studied. The influence of the substitution pattern of the aromatic ring and the configuration of the centre of chirality on the Cotton effects appearing in various wavelengths ranges are discussed.

Treatment of 2- O -benzoyl ( 1 ) and 2- O -acetyl ( 5 ) derivatives of benzyl 4,6- O -benzylidene-3- O -(2,3,4-tri- O -acetyl-α- l -rhamnopyranosyl)-β- d -galactopyranoside under Zemplen conditions (catalytic amount of sodium methoxide in methanol) gave partially deacylated disaccharides in which the 2- O -acyl groups were retained. Likewise, a similar result was obtained with the β- l -rhamnopyranosyl analogue ( 3 ) of 1 . This anomalous reaction was used in a synthesis of the title trisaccharide ( 17 ) and of methyl 4,6- O -benzylidene-3- O -(2,3:4,6-di- O -isopropylidene-α- d -mannopyranosyl)-α- d -glucopyranoside, an intermediate for the synthesis of 2- O -glycosyl-3- O -(α- d -mannopyranosyl)- d -glucoses.

A new, very convenient and sensitive “in situ” method has been developed for the determination of the absolute configuration of chiral compounds, which can bind to the axial position of [Rh2(O2CCF3)4] (5) and induce circular dichroism within its electronic absorption bands. The CD spectra of the “in situ” complexes of chiral alcohols, ethers (including epoxides), olefins, and ketons with 5 show up to 5 Cotton effects (A – E) in the 600 – 300 nm range. This method works well for chiral secondary alcohols and monoolefins. For these compounds tentative rules are proposed, which correlate the absolute stereochemistry with the sign of certain Cotton effects of their complexes. A rule for the sign of band E for alcohols and a quadrant rule for the sign of band C for olefins can be applied. Olefins induce unexpected strong Cotton effects in presence of 5 giving evidence for a relatively stable π-bond between olefin and rhodium atom.

Some oximes of 4- and 6-ketosteroids, of des-A-5-keto-steroids, and the related compounds 31 and 33 have been synthesized. In three cases stable B / Z pairs are formed which could be separated. The CD-spectra of all compounds have been measured. The Cotton effects around 217 run of the 6-hydroxyimino-5α-steroids (1 – 18, 34, 36) are negative, those of the corresponding 4-analogues (20 – 23) are positive. A similar relationship holds for the des-A-steroidoximes 24 – 26 vs. 27, and the syn-oximes 34/36 vs. their anti-analogues 35/37. This Cotton effect can, therefore, be used for the determination of the configuration of such oximes. The Cotton effects below 200 nm do not always show similar regularities.

The relationship between structure and circular dichroism was studied for a series of cardenolides including some compounds with saturated lactone ring.

Cholesteno Indoles, I. – Preparation of 1′H-5α-Cholest-2-eno[3,2-b]indoles 1′H-5α-Cholest-2-eno[3,2-b]indole (1a), the corresponding N-methyl, N-acetyl, and N-formyl compounds 1b–d, as well as the respective methoxy derivatives 2b–5d have been synthesized as model compounds for intended CD investigations. Application of the Fischer indole synthesis afforded the compouds 1a–5a which were N-methylated to 1b–5b, N-acetylated to 1c–5c, and N-formylated to 1d–5d.