Showing papers on "Total synthesis published in 1981"
271 citations
TL;DR: The specific incorporation per C4 unit, 3.3%, calculated from 13C NMR data (Table I), is identical with that obtained from I4C radioactivity measurements.
Abstract: 3210-3213 The specific incorporation per C4 unit, 3.3%, calculated from 13C NMR data (Table I), is identical with that obtained from I4C radioactivity measurements. The signals due to the I3C-enriched carbon atoms in the proton decoupled I3C NMR spectrum of labeled retronecine appear as multiplets (Table
214 citations
TL;DR: In this paper, the authors reported the synthesis of erythromycin (2) from la in optically active form, which involves the glycosidation of a suitable derivative of la with L-cladinose and D-desosamine and the generation of the C-9 ketone functionality.
Abstract: In the preceding paper' we described the preparation of the
key lactone intermediate la in optically active form. In this paper we report the synthesis of erythromycin (2) from la. In essence,this transformation involves the glycosidation of a suitable derivative of la with L-cladinose and D-desosamine and the generation of the C-9 ketone functionality.
175 citations
TL;DR: In this paper, the authors reported a successful transformation of 2 to 12 (synthetically equivalent to erythronolide A) via lactonization and also demonstrate that the proper functionalization of a substrate is critical for the successful lactonisation.
Abstract: In reporting a total synthesis of erythromycin (la) we described in the preceding paper1 the synthesis of the erythronolide A seco acid derivative 2 in optically active form. In this paper we wish to report a successful transformation of 2 to 12 (synthetically equivalent to erythronolide A) via lactonization and also demonstrate that the proper functionalization of a substrate is critical for the successful lactonization.
142 citations
121 citations
TL;DR: In this article, two general methods, Method A and Method B, were described to synthesize epidithiapiperazinediones, and a total synthesis of racemic and optically active gliotoxin was achieved by using Method A.
91 citations
89 citations
TL;DR: A strategy suitable for the synthesis of larger peptides is proposed, using a water‐soluble carbodiimide for the fragment‐condensation reactions together with 1‐hydroxybenzotriazole as the additive.
Abstract: A strategy suitable for the synthesis of larger peptides is proposed. It involves the following four considerations: (1) all of the side-chain functional groups are protected by benzyl-type protective groups; (2) a water-soluble carbodiimide, 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide, is used for the fragment-condensation reactions together with 1-hydroxybenzotriazole as the additive; (3) all the protective groups are cleaved simultaneously by the HF method in the final stage of the synthesis; and (4) side products formed are detected and removed by an efficient high-performance liquid chromatography procedure. The usefulness of these procedures is demonstrated taking the synthesis of human parathyroid hormone [hPTH(1–84)] as an example.
87 citations
TL;DR: Results indicate the stereospecificity of platelet activation induced by PAF, and the intermediates in synthesis are easier to purify, with better yields.
85 citations
84 citations
TL;DR: In this paper, Lysergic acid was synthesized from 4-hydroxymethyl-1-tosylindole by a sequence of 9 steps and the crucial thermolysis involved the in situ generation of the transient diene III which undergoes an intramolecular cycloaddition to a C, N-double bond at 200° and at low stationary concentration of III.
Abstract: (±)-Lysergic acid (1) has been synthesized from 4-hydroxymethyl-1-tosylindole (2) by a sequence of 9 steps. The crucial thermolysis 9 10 involves the in situ-generation of the transient diene III which undergoes an intramolecular cycloaddition to a C, N-double bond at 200° and at low stationary concentration of III.
TL;DR: In this paper, total synthesis of (&)-desacetamidoisoolchicine (2b) and (&)-colchicines (la) have been achieved.
Abstract: Total syntheses of (&)-desacetamidoisoolchicine (2b) and (&)-colchicine (la) have been achieved. Key features of the synthetic sequence are the facile incorporation of a tropolone dication equivalent via ketone 6 and introduction of the 7-acetamido group. Some of the mechanistic details of the conversion of alcohol 7 to dihydrotropolone 8 and alcohols 14a,b to ester 19 are discussed. Colchicine (la), one of the major alkaloid constituents of the
TL;DR: In this paper, the arene-olefin meta-photocycloaddition is shown to provide the basis for an effective and general approach to polyquinane natural products as demonstrated by the synthesis of (±)-isocomene ( 5 ) in five steps based on Z-2bromo-2-butene and 2-bromotoluene.
TL;DR: The first total synthesis of ditryptophenaline was described in this paper and the absolute configuration was determined, and the total synthesis was shown to be NP-complete. But this was not the case for all drugs.
TL;DR: In this paper, flash vacuum pyrolysis of functionalized tricyclo|5.2.1.02,3|decenone epoxide 5, and acetals 3 and 4 affords cyclopentadienone Epoxide 6 and acetal 10 and 8, respectively.
TL;DR: L-Serine was transformed in 8 steps into (4R,5S)-2,2-dimethyl-4-[(Z)-3-pentadecenyl]-1,3-dioxan-5-amine, a chiral e,ζ-unsaturated amine that was subjected to intramolecular aminomercuration and acid hydrolysis to give (−)- deoxoprosopinine and (−)-deoxoposophyll
Abstract: L-Serine was transformed in 8 steps into (4R,5S)-2,2-dimethyl-4-[(Z)-3-pentadecenyl]-1,3-dioxan-5-amine. This chiral e,ζ-unsaturated amine was subjected to intramolecular aminomercuration and then acid hydrolysis to give (−)-deoxoprosopinine and (−)-deoxoprosophylline.
TL;DR: In this paper, a (R,R)-phytol uith highly stereochemioal purity in both absolute and geometrical aonfigurations was achieved by utilizing the SNZ type ring-opening reaction of (R)-β-methyl-β-propiolactone.