2-Aminothiophene. Heterocyclization of benzylthionitriles

Synthesis of unstable 2-aminothiophene by way of its hydrochloride salt has been achieved in excellent yield. The key reaction in the scheme involves a novel heterocyclization of benzylthionitriles, which would appear to have general utility. Spectral and physical properties are tabulated and a possible mechanism is proposed.     

Heterocyclic compounds. VI. Synthesis of poly nuclear thienopyrimidine derivatives

Quinazoline derivatives have received great interest because of their potential biological activity. This communication describes a facile method for the synthesis of substituted thiophenopyrimidones. 2-Amino-3-earbethoxy-4,5-tetramethylenethiophene on heating with substituted imidoyl-chlorides, iminoethers, iminothioethers or thioamides affords thiophenopyrimidones. By using this method a number of such compounds of varying complexity were synthesized which are otherwise not so easily accessible.     

Heterocyclic amines. A convenient synthesis of 3,5-diamino-1,2,4-triazine derivatives

A facile synthesis of 3, 5-diamino-1, 2,4-triazines (I) via condensations in acidic media of acylnitriles with aminoguanidine and subsequent base-catalyzed cyclization of the resulting acylnitrile amidinohydrazones (IV) is described.     

Oxasilacyclopropane. Isolation and characterization

A crystalline oxasilacyclopropane was isolatedby the reaction of photochemically induced dimesitylsilylene with 1,1,3,3-tetramethyl-2-indanone, and the exact structure of the oxasilacyclopropane was confirmed by X-ray crystal analysis.     

Heterocyclic N-Glycosides. VI. The reaction of glycosyl azides with propiolic acid and methyl propiolate

The synthesis of a series of N-glycosyl-v-triazoles has been accomplished by the 1,3-dipolar cycloaddition of several glycosyl azides to methyl propiolate and propiolic acid. In most of the cases the two isomeric v-triazoles were obtained. Structural and anomeric configuration assignments for the N-glycosides obtained were made on the basis of NMR data. None of the compounds possessed appreciable biological activity against HeLa cells in culture and mouse Sarcoma 180.     

Arylation of adamantanamines: VI. Palladium-catalyzed arylation of amines and diamines of the adamantane series with 3-bromopyridine

Palladium-catalyzed amination of 3-bromopyridine with amines of the adamantane series in the presence of Pd(dba)₂/L [L = 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl or 2-dimethylamino-2′-dicyclohexylphosphinobiphenyl] gave the desired N-(pyridin-3-yl)-substituted amines in 74–97% yields. Diamines of the adamantane series reacted with 2 equiv of 3-bromopyridine in a complicated fashion to produce mono- and triaryl-substituted derivatives as by-products, while the yields of N,N′-diarylation products were 18–56%.     

Heterocyclic rearrangements. Phenylhydrazones and N-methyl-N-phenylhydrazones of 3-acylisoxazoles

The reaction of 3-benzoyl-5-phenylisoxazole ( 4 ) and 3-acetyl-5-methylisoxazole ( 5 ) with phenylhydrazine and N-methyl-N-phenylhydrazine has been investigated and the reactivity of (E)- and (Z)-phenylhydrazones and N-methyl-N-phenylhydrazones has been studied.     

VI. Synthesis of Heterocyclic Analogs of γ-Aminobutyric Acid from 3,5-Dinitrobenzoic Acid

A series of 7-carboxy-3-R-1,5-dinitro-3-azabicyclo[3.3.1]non-6-enes was synthesized by reduction of 3,5-dinitrobenzoic acid with sodium borohydride followed by Mannich reaction with formaldehyde and primary amines. The mechanism of decomposition under electron impact of the 3-azabicyclo[3.3.1]nonane was established. Enthalpies of formation of compounds synthesized were calculated by semiempirical PM3 method.     

Heterocyclic amines for the construction of peptoid oligomers bearing multi-dentate ligands

Peptoids are oligomers of N-substituted glycine that can be readily assembled using haloacetic acids and primary amines as synthons. Here, we report the synthesis and characterization of three new heterocyclic amines, 2-(2,2′:6′,2″-terpyridine-4′-yloxy)ethylamine, 2-(1,10-phenanthroline-5-yloxy)ethylamine and 8-hydroxy-2-quinolinemethylamine, and their incorporation into a series of different peptoid oligomer sequences. Since the heterocycles are all known to coordinate metal ions, the peptidomimetic products are designed to bind metal species with the potential for applications in catalysis and materials science.     

Human calcitonin. I. Isolation and characterization

Two highly active calcitonin peptides, M with 32 amino acids, and D a dimer of M, were isolated from a large human mediastinal C cell tumour. D can easily be transformed into M by the action of 1N ammonia; D and M afford two different sulphoxides, but all four peptides yield the same product upon oxidation with performic acid. Both D and M have a potency of about 120 MRC units/mg dry weight; their sulphoxides, by contrast, are almost inactive. Tryptic digestion of M produces an N-terminal octadecapeptide (Tr_I) and a C-terminal tetradecapeptide (Tr_II), the latter being also obtained from D. Amino acid analysis and other analytical data are presented. The structure of the human calcitonin peptides D and M is thus very different from that of porcine α-thyrocalcitonin.     

Heterocyclic variants of the 1,5-benzodiazepine system. VI. Derivatives of 2-methylthio-4-(p-r-phenyl)-3H-1,5-benzodiazepines

Ethyl 3-[3H-1,5-benzodiazepin-2-yl]carbazates II were prepared in moderate yields from the title compounds and ethyl carbazate. The compounds II were easily transformed into 1H-s-triazolo[4,3-a][1,5]benzodiazepin-1-ones III via a one-step procedure. Reaction of triazolo-1,5-benzodiazepinones III with sodium hydride in methyl iodide gave a mixture of products from which were isolated two compounds IV and V . The structure of all products was confirmed by ir, ¹H nmr and mass spectrometry.     

Nitrosyl derivatives of group VI metals containing monodentate amines

Summary Passage of a slow stream of nitric oxide through a benzene solution of M(CO)₅(Am), (M = Mo and W; Am = BuNH₂, C₆H₁₁NH₂, PhCH₂NH₂, C₅H₁₁N, C₅H₅N and BuNO) yielded dimeric [M(NO)₃(Am)]₂ complexes which have been characterized by elemental analysis, magnetic data and i.r. spectra. The i.r. data indicate the presence of terminal as well as of bridging nitric oxide in the complexes.