Vitamin B6 analogs

3-O-Methylpyridoxal phosphate and 3-O-methylpyridoxamine phosphate were synthesized and their UV spectra were studied.See [7] for communication IX.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 368–372, March, 1971.     

Vitamin B6 analogs

4-Acetyl-3-hydroxy-5-hydroxymethyl-2-methylpyridine 5-phosphate (IV) was synthesized by oxidation of 3-hydroxy-5-hydroxymethyl-4-(-hydroxyethyl)-2-methylpyridine 5-phosphate (III) with chromic anhydride. Compound III was obtained by phosphorylation of 3-hydroxy-5-hydroxymethyl-4-(-hydroxyethyl)-2-methylpyridine with polyphosphoric acid (PPA). The UV and PMR spectra of the synthesized compounds were studied.See [1] for communication XIV.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 499–503, April, 1971.The authors sincerely thank Academician A. E. Braunshtein for his constant interest in this work, V. I. Ivanov and A. F. Vanin for their fruitful discussions, and K. F. Turchin and I. I. Chervin for kindly providing the possibility for obtaining the PMR spectra.     

Benzo[b]thiophene derivatives I. 6-methoxybenzo[b]thiophene analogs of plant growth regulators

The acid catalyzed ring closure of an appropriately substituted phenyl ketoester sulfide served as the initial reaction in the synthesis of several 3,4- and 3,6-disubstituted benzo[b]thiophenes. One of these compounds, 4-methoxybenzo[b]thienyl-3-acetic acid, showed marked plant growth enhancement.     

Vitamin D side chain triazole analogs via cycloaddition `click' chemistry

Cycloaddition of a vitamin D side chain terminal acetylene with phenyl azide and separately with a vitamin D side chain terminal azide produced the corresponding 1,2,3-triazole monomeric and dimeric analogs of 1α-hydroxyvitamin D₃ in good yields.     

Benzo[b]thiophene derivatives. XXVII. 5-methoxy-6-halo-3-β-acetamidoethylbenzo[b]thiophenes,blocked analogs of melatonin

The preparation of the 6-fluoro and 6-chloro analogs of the title compound is described, in a seven-step synthesis giving 30-40% overall yields. All intermediates have been isolated and characterized, including important by-products, such as the corresponding benzo[b]thienyl-3-acetic acids, and 3-methylbenzo[b]thiophenes. Cyclization of the 3-halo-4-methoxyphenylthioacetoacetic esters gave more ortho-cyclization in the chlorine case than was observed for the fluorine derivative. The title compounds were shown to have weak antiovulatory action, with the fluoro analog most active.     

α-Alkenyl analogs of phosphorylcholines

The new type of α-alkenyl esters of phosphorus acids containing ammonium or phosphonium groups in unsaturated radicals as well as carbonyl or other complexes of Mo, Cr, W, Mn, or Pt with such organophosphorus ligands have been described. The alkenyl phosphates undergo dealkylation upon heating to give betaines. This conversion results in a substantial decrease of an anticholinesterase activity of the compounds and in a sharp rise of their hydrolytic stability. The prototropic rearrangement is observed for the phosphonium betaines.     

Selenium-Sulfur analogs. 6. Selenoisosteres of levamisole

A series of three new isosteres of levamisole was prepared by the substitution of the phenyl ring by the thienyl and selenienyl moieties and of the thiazole group by selenazole. The physiochemical properties and infrared spectra of the sulfur- and selenium-containing analogs were very similar. Differentiation was mostapparent in the nuclear magnetic resonance spectra where the α- and β-protons of the selenienyl compounds were shifted downfield relative to those of the corresponding thienyl compounds. With deuterated thiofluoroacetic acid as the solvent, a more rapid exchange was observed for the α-proton of the selenienyl ring of compounds 17 and 18 compared to that observed for compound 16 .     

紫外分光光度法测定维生素B6

维生素B6是2-甲基-3羟基-4,5-二(羟甲基)吡啶盐酸盐,已报道的测定方法有示波沉淀滴定法,导数单扫示波伏安法,药物PVC膜电极法,高氯酸非水滴定法等。这些测定方法操作均比较繁琐。鉴于在pH8条件下维生素B6与4-氨基安替比啉被过二硫酸铵氧化偶合可生成稳定的黄色产物,本文建立了VB6的紫外分光光度测定法,此方法操作简便,结果准确,适用于实际分析。     

Synthesis of heterocyclic analogs of α-methyldopa

The condensation of various halomethyl heterocycles with the potassium salt of the alanine derivative 3, followed by hydrolysis, gave a series of novel 3-heterocyclic-2-methylalanines.     

Reductive photocyclization of benzo[b]furans and their analogs

The UV irradiation of substituted 2,3-diphenylbenzo[b]furans and of 2,3-diphenyl-5-t-butylfuran in n-propylamine gives 1,4-dihydro derivatives of the corresponding aromatic cyclized compounds. This reaction does not involve a photoreduction. It can be concluded from deuterium labelling experiments that H atoms of the alkyl chain of n-propylamine are incorporated in the product. When the solvent is not an unhindered primary amine, only totally aromatic photocyclized products are obtained. It is proposed that hydrogens eliminated during formation of the isolated compounds are released in a reductive form and not as radicals. This is supported by the fact that acenaphthylene is reduced when irradiated in n-propylamine together with 2,3-diphenylbenzo[b]furan under conditions which do not promote, photoreduction. This seems to be a general finding in that the irradiation of stilbene in n-propylamine to acenaphthylene is the same as that of 2,3-diphenylbenzo[b]furan.     

Synthesis of 6-deoxo-24-epiteasterone and its analogs

Selective reduction of the C⁸=C¹⁴ double bond in 3-hydroxyergosta-8(14),22-dien-15-one, followed by cis-hydroxylation of the double bond in the side chain and reduction of the 15-oxo group gave new 3β-hydroxy-6-deoxobrassinosteroids, their 22S,23S isomers, and the corresponding esters. The side chain in the products is identical to that in such known natural brassinosteroids as 24-epibrassinolide and 24-epicastasterone.     

维生素B6树脂法脱色初探

合成得到的维生素 B6 ( Vit B6 ) ,粗产品为黄色到棕色粉末 ,必须经 2次活性炭脱色、结晶 ,才能合格 .粉末炭脱色后一般不能回收重复使用 ,部分产品因吸附在活性炭上会造成产品收率降低 ,而且脱色工艺中常需热过滤 ,开放式的操作会对工作环境造成污染 .大孔吸附树脂用于天然产物的提取分离 ,近年来发展十分迅速 ,在药物、抗生素提纯、工业废水、废液的净化等方面也得到广泛应用 ,在天然色素的提取[1 ,2 ] ,产品的脱色方面也显示出了独特的作用[3,4] .本文探讨了用吸附树脂法对 Vit B6的脱色纯化 .Vit B6标样和粗品由上海新亚药厂提供 ,H…     

Enantioselective straightforward access to benzo[b]thiophene analogs of Azatoxin

Horner-Wadsworth Emmons olefination followed by asymmetric hydrogenation allowed the first synthetic access to the chiral thiotryptophan with good enantiomeric excess. Oxazolidinone formation followed by a Pictet–Spengler condensation provided the benzothiophenic analog of Azatoxin.     

Synthesis of 6-thia analogs of the natural neurosteroid allopregnanolone

A procedure is described for the preparation of 6-thiapregnanes in five steps from pregnenolone via a 5-oxo-7-iodo-secopregnane intermediate. The 6-thiasteroid obtained was converted into 6-thia-allopregnanolone and its sulfoxide and sulfone derivatives. The trans stereochemistry at the A/B ring junction was accomplished by stereoselective reduction of an intermediate hemithioketal with triethylsilane/BF₃·Et₂O. The compounds synthesized are analogs of natural neurosteroids, and exhibited GABA_A receptor activity comparable to allopregnanolone.