1,3-Thiazepines. 1. Synthesis and spectral properties of 2-iminohexahydro-1,3-thiazepines

By reaction of 4-amino-1-butanol with isothiocyanates RNCS, we have synthesized N-(4-hydroxybutyl)-N-R-thioureas, which by cyclization when treated with hydrohalic acids are converted to the corresponding 2-(R)-imino)hexahydro-1,3-thiazepines. The structure of the compounds obtained has been confirmed by PMR, IR, and mass spectra.Institute of Phytochemistry, Academy of Sciences of the Republic of Uzbekistan, Tashkent 700170. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 128–133, January, 1997.     

1,3-Thiazepines. 5. Study of 2-Phenyl(benzyl)iminohexahydro-1,3-thiazepines and Their Derivatives by 13C Spectroscopy

We have studied the ¹³C NMR spectra of 2-phenyl- and 2-benzyliminohexahydro-1,3-thiazepines, and also their alkyl, acyl, carbamoyl, and thiocarbamoyl derivatives. We have shown that introducing substiuents both into the 2 position and into the 3 position of the thiazepine ring mainly affects the chemical shifts for the C(4) of the heterocycle.     

1,3-Thiazepines. 6. UV Spectroscopic and Theoretical Study of the Electronic Structures of 2-Aminotetrahydro- and 2-Iminotetrahydro-1,3-thiazepines

On the basis of studies of the electronic absorption spectra and quantum-chemical calculations of the energies and bond orders of a series of N-acetyl-N-aryl substituted 2-amino-4,5,6,7-tetrahydro-1,3-thiazepines and N-aryl substituted 2-iminohexahydro-1,3-thiazepines it has been concluded that the reason for the weak basicity of the ring nitrogen atom of the former is the acceptor properties of the amide carbonyl which obstructs the interaction of the unshared pair (USP) of this atom with the phenyl ring; in the case of the derivatives of hexahydroazepine the strengthening of the basic properties of the exocyclic nitrogen atom is associated with the conjugation of its USP with the -electrons of the benzene ring, which is strengthening by delocalisation of the USP of the sp³-hybridized ring nitrogen atom into the azomethine bond.     

1,3-Dimethoxy-1,3-dimethyl-1,3-diphenyl- and 1,3-dimethoxy-1,3-tetraphenyldisiloxanes: synthesis and structure

Russian Chemical Bulletin - 1,3-Dimethoxy- 1,3-dimethyl- 1,3-diphenyl- and 1,3-dimethoxy- 1,3-tetraphenyldisiloxanes were synthesized. Their structures were confirmed by IR and NMR spectroscopy....     

1,3-Diphenylpropane-1,3-diamines XI. Conversion of a 3-hydroxy-1,3-diphenylpropan-1-one to 1,3-diphenylpropane-1,3-diamines

Summary Highly diastereoselective BH₃/THF syn-reduction of the 3-hydroxy-1,3-diphenylpropan-1-one/BBr₃ complex3/BBr₃ (cf.Sarko) afforded themeso-diol4, whereas racemate5 was obtained by BH₃/THF reduction without complexation. Mesylation, exchange of mesylate by azide, and reduction with SnCl₂/thiophenol led to the diamines10 and11 which were also produced by reductive N-N cleavage of the 4,5-dihydropyrazole13.Dedicated to Prof. Dr.G. Wurm, Berlin, on the occasion of his 60^th birthday     

A 1,3-dihydro-1,3-azaborine debuts

We present the first synthesis and characterization of a 1,3-dihydro-1,3-azaborine, a long-sought BN isostere of benzene. 1,3-Dihydro-1,3-azaborine is a stable structural motif with considerable aromatic character as evidenced by structural analysis and its reaction chemistry. Single crystal X-ray analysis indicates bonding consistent with significant electron delocalization. 1,3-Dihydro-1,3-azaborines also undergo nucleophilic substitutions at boron and electrophilic aromatic substitution reactions. In view of the versatility and impact of aromatic compounds in the biomedical field and in materials science, the present study further expands the available chemical space of arenes via BN/CC isosterism.     

Optisch aktives 1,3-Diferrocenyl-1,3-diphenyl-allen

The title compound 2 was prepared by thermal dehydration of 1,3-diferrocenyl-1,3-diphenyl-propenol (24) with 70% yield.24 was accessible from 1,3-diferrocenyl-propanedione-1,3 (25) in two steps with 10% overall yield: Treatment of25 with phenyllithium gave 1,3-diferrocenyl-3-phenyl-propenone (8) which after repeated reaction with phenyllithium afforded24.Partial optical resolution of2 was achieved by chromatography on triacetyl cellulose in ethanol, whereby both (+)- and (–)-2 were obtained with different enantiomeric purities as could be deduced from the CD-spectra with -values of +0.18 and –1.64, resp., at 480 nm.Attempts to prepare 1,3-diferrocenyl-allene and 1,3-diferrocenyl-1-phenyl-allene failed. In this context several 1,3-diferrocenyl-propenols,-propenones,-propenes,-propanones,-propanes and-butadienes were obtained.

62. Mitt.:M. Benedikt undK. Schlögl, Mh. Chem.109, 805 (1978).     

Oxidation reactions of 1,3-diphenylpropane-1,3-dione

The free radical scavenging properties and possible antioxidant activity of 1,3-diphenylpropane-1,3-dione (1) are reported. Pulse radiolysis technique was employed to study the one-electron oxidation of 1 with various radicals viz. CCl₃O₂ ^•, N₃ ^• and^•OH in homogeneous aqueous solution. All these radicals reacted with 1 under ambient conditions at almost diffusion controlled rates producing transient species with an absorption maximum around 420 nm that decayed at first order rates. The transient absorption peak was shifted in the case of CCl₃OO^• radical reaction with 1 due to change in the polarity of the medium. Formation of a stable product with a broad absorption band starting from 400 nm and cut off at 230 nm was observed in the oxidation of 1 with^•OH and^•N₃ radicals. In a biological system also, 1 showed significant inhibitory activity against Fe²⁺-mediatedlipidperoxidation. Based on these observations, a suitable mechanism for the oxidation of 1 has been proposed.     

Stereocontrolled 1,3-phosphatyloxy and 1,3-halogen migration relay toward highly functionalized 1,3-dienes

A double migratory cascade reaction of α-halogen-substituted propargylic phosphates to produce highly functionalized 1,3-dienes has been developed. This transformation features 1,3-phosphatyloxy group migration followed by 1,3-shifts of bromine and chlorine as well as the unprecedented 1,3-migration of iodine. The reaction is stereodivergent: (Z)-1,3-dienes are formed in the presence of a copper catalyst, whereas gold-catalyzed reactions exhibit inverted stereoselectivity, producing the corresponding E products.