ChemInform Abstract: A New Synthesis of Vinblastine Derivatives. Part 3. Synthesis and Reactions of 21,Nb‐seco‐Cleavamine Derivatives as Precursors of 20′‐Deethyl‐20′‐deoxyvinblastine and (.+‐.)‐16α‐Methoxycarbonyl‐20‐deethyl‐15,20‐dihydrocleavamine.

Schill, Gottfried; Priester, C. U.; Windhoevel, U. F.; Fritz, Hans

doi:10.1002/chin.198803330

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“…Diethyl malonate was coupled with bromoacetaldehyde diethylacetal to give 11 in good yield (64%) after distillation (Scheme 3). This reaction is described in the literature employing sodium ethoxide [22][23][24][25] or sodium hydride 26,27 as base; nevertheless, we attempted the alkylation using potassium carbonate, a modified procedure which was found to be very practical. The diethyl acetal moiety of 11 was cleaved using aqueous TFA, and the resulting aldehyde, which by TLC and NMR was shown to be pure, was immediately protected as an N-Boc N,Oacetal.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Aldehyde Building Blocks Protected as Acid Labile N-Boc N,O-Acetals: Toward Combinatorial Solid Phase Synthesis of Novel Peptide Isosteres

Groth

Meldal

2000

J. Comb. Chem.

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The synthesis of (RS)-3'-tert-butoxycarbonyl-perhydro-1', 3'-oxazine-2'-yl acetic acid and the syntheses of the simple and C-2 substituted 3'-tert-butoxycarbonyl-perhydro-1',3'-oxazine-2'(RS)-yl propionic acids from simple starting materials are presented. The simple compounds were prepared from 1,3-propanediol and 1, 4-butanediol, respectively, via a short series of facile steps, in 70% overall yield in both cases. For the syntheses of the C-2 substituted compounds of the longer homologue, (RS)-3'-tert-butoxycarbonyl-perhydro-1',3'-oxazine-2'-yl propionic acid, a malonic ester route was selected, thus allowing easy incorporation of various side chains. The stability of the novel aldehyde protection group, the N-Boc N,O-acetal moiety, under various acidic conditions was investigated, and it was found to cleanly and rapidly yield the aldehyde under strong acidic conditions or, if desired, slower under less harsh conditions. As a demonstration of the use of the building blocks, one building block was coupled to a solid support and, after unmasking of the aldehyde, submitted to three different types of nucleophilic reactions (Pictet-Spengler condensation, reductive amination, Horner-Wadsworth-Emmons olefination) followed by further chemical modification, and the identity of the structures were verified after cleavage from the resin.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Aldehyde Building Blocks Protected as Acid Labile N-Boc N,O-Acetals: Toward Combinatorial Solid Phase Synthesis of Novel Peptide Isosteres

Groth

Meldal

2000

J. Comb. Chem.

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ChemInform Abstract: A New Synthesis of Vinblastine Derivatives. Part 3. Synthesis and Reactions of 21,Nb‐seco‐Cleavamine Derivatives as Precursors of 20′‐Deethyl‐20′‐deoxyvinblastine and (.+‐.)‐16α‐Methoxycarbonyl‐20‐deethyl‐15,20‐dihydrocleavamine.

Abstract: In a new concept for the synthesis of the title vinblastine derivative the ester (VIIb) is prepared starting from the amine (I).

Cited by 1 publication

References 1 publication

Synthesis of Aldehyde Building Blocks Protected as Acid Labile N-Boc N,O-Acetals: Toward Combinatorial Solid Phase Synthesis of Novel Peptide Isosteres

Synthesis of Aldehyde Building Blocks Protected as Acid Labile N-Boc N,O-Acetals: Toward Combinatorial Solid Phase Synthesis of Novel Peptide Isosteres

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