Synthesis of (±)-Methyl Bishomononactate,a Monomeric Component of Polynactin Antibiotics

The synthesis of (±)-methyl bishomononactate, one of the monomeric components of polynactin antibiotics (macrotetrolides), was achieved via cis-selective iodoetherification as the key step.     

Total Synthesis of (±)-Millettone

(±)-Millettone (14) was synthesized.     

Total Synthesis of (±)-Chokolic Acid A

The fungitoxic sesquiterpene (±)-chokolic acid A (1) was synthesized stereoselectively by starting from 2-methoxycarbonyl-(3-isopropenyl)cyclopentanone (2) in a 9% overall yield from 10 steps.     

Chemoenzymic Synthesis of Pα-Methyl Deoxynucleoside Triphosphates

Abstract

5′-O-(methylphosphonyl)-N-(phenylacetyl)-2 ′-deoxycytidine, deoxyadenosine and deoxyguanosine were pyrophosphorylated and the resulting N-protected P α-methyl nucleoside triphosphates were deblocked by treatment with penicillin amidase at pH 7.8, 25°C to give P α-methyl nucleoside triphosphates.     

A Simple Total Synthesis of (±)-(δ-Cadinene

This paper reports on a total synthesis of racemic δ-cadinene (2), which had been obtained previously in optically active form by acid-catalyzed cyclization of (–)-germacrene D. The Robinson annelation using cyclohexenone enamine (12) proceeded stereoselectively to form δ-cadinenone (3), whose oxygen was removed by the thioketal–Raney Ni method to produce δ-cadinene.     

Synthesis and Biological Activity of ( + )-Pyrenolide B

The synthesis and biological activity of ( + )-pyrenolide B (1) and related compounds are described. The known (Z)-2-decen-9-olide (7) prepared via decan-9-olide (6) from 2-ethoxycarbon- ylcyclononanone (4) was converted to 9 by the deconjugative process, which, upon oxidation with m-chloroperbenzoic acid, led to the epoxy lactone 10. Base-promoted epoxide ring opening of 10 and subsequent oxidation furnished keto lactone 8, which, on treatment with phenylselenenyl chloride and subsequent oxidative elimination, provided ( + )-pyrenolide B (1). The antimicrobial activity of (±)-1, 6, 7, 8, 9, 10a, 10b and 11a was examined against fungi and yeast.     

The Total Chemical Synthesis of Monocyte Chemotactic Protein-1 (MCP-1)

The affinity-based N^α-amino protecting group tetrabenzo [a,c,g,i]fluorenyl-17-methoxycarbonyl (Tbfmoc) has been utilized as a hydrophobic probe to allow the simple, quick and highly effective isolation of a 76 residue cysteine-containing protein (MCP-1). The base-labile Tbfmoc group can be removed under very mild conditions, which preserve the thiol-con taining protein in the reduced state. Oxidative folding was then used to furnish the biologically active β-chemokine MCP-1.     

N-(1-Methyl)cyclopropylbenzylamine: A novel inactivator of mitochondrial monoamine oxidase

N-(1-Methyl)cyclopropylbenzylamine was synthesized and shown to inactivate pig liver mitochondrial monoamine oxidase. Inactivation is time-dependent, concentration dependent, protected by the substrate and product of the enzyme, and is not reversed by exhaustive dialysis. Unlike N-cyclopropylbenzylamine, the adduct formed between N-(1-methyl)cyclopropylbenzylamine and monoamine oxidase is stable to treatment with benzylamine. A mechanism for the inactivation is proposed.     

Diterpenoid Total Synthesis

A total synthesis of racemic 4-epipimaric and 4-episandaracopimaric acids is described.     

Diterpenoid Total Synthesis

Total syntheses of (±)-steviol (IIa) and (±)-kaur-16-en-19-oic acid (III) were accomplished. A synthesis of methyl (±)-8α-carboxymethylpodocarpan-13-on-19-oate (IVa), a degradation product of steviol, was also described.     

天然抗癌药物紫杉醇的全合成

紫杉醇为著名的抗肿瘤天然产物,来源有限,化学合成是制备紫杉醇的可能途径之一。本文综述了目前已公开报道的6条全合成紫杉醇的路线。     

三粒小麦黄酮的全合成

本文以2,4,6-三羟基苯乙酮为原料,经羟基保护、酰化反应、Baker-Venkataraman重排、成环反应和脱保护五步得到目标产物三粒小麦黄酮,总收率约7.4%。     

Total Synthesis of dl-Deguelin

Starting with resorcinol, the total synthesis of dl-deguelin (VI) was accomplished. In the course of this investigation, dihydrodeguelic acid (II), dihydroisodeguelic acid (X), dihydro-dehydrodeguelin (III), dehydrodeguelin (IV), dl-deguelol (V) and dihydro-β-rotenonone (XI) were prepared. But the reduction of dihydrodehydrodeguelin (III) to dihydrodeguelin (XII) resulted in failure. The preparation of dihydrodeguelol (XIIIa), its acetate (XIIIb) and dihydro-desoxy-Δ¹¹-dehydrodeguelin (XIV) was also described.     

丁香脂素的全合成

本文以丁香醛为原料,经过与丙二酸Knoevenagel缩合,甲酯用LiAlH4还原得到了芥子醇。芥子醇在光照下氧化偶联,得到了丁香脂素。总产率为43.68%。     

Total Synthesis of dl-Variotin

The total synthesis of dl-variotin is described.     

Total Synthesis of Destruxin B

Rats were divided into low casein diet and high casein diet fed groups, and the fatty acid composition of liver mitochondrial phosphatides was analyzed. It was found that in liver mitochondrial phosphatides the value of arachidonic acid decreased slightly, and that of the polyenoic fatty acid which was infered as 4, 7, 10, 13, 16-docosapentaenoic acid increased by low casein diet. The analysis was performed also on whole liver phosphatides. There was no great difference between the fatty acid composition of whole liver and liver mitochondrial phosphatides     

Total Synthesis of Sclerotinin A

Sclerotinin A (3,6,8-trihydroxy-3,4,5,7-tetramethyl-3,4-dihyroisocoumarin: 1), a metabolite of Sclerotinia sclerotiorum, was first totally synthesized. The pentenone ring of 2,3,4,6-tetramethyl-5,7-dimethoxyindanone (VII_a) which was obtained from 2,4-dimethylresorcinol dimethyl ether (VI) through a new synthetic process, was cleavaged oxidatively, and demethylated to I. Sclerotinin A was also yielded from indanone dibenzyl ether (VII_b) by the same method and reductive debenzylation.