Hoffmann-la Roche Inc.

Urs Oskar Hengartner

Willy Leimgruber

Andrew D Batcho

John William Scott

Donald H Valentine, Jr

Pius Anton Wehrli

Gilbert Reymond

Valdemar Toome

The preparation of racemic and optically pure tryptophans is described. The D-enantiomers of the 6-substituted compounds possess a potent sweetening capability. Novel intermediates are also disclosed.

Pyrroles and pyrrolidines

A new process for preparing 1-(3-oxo-2,6,6-trimethyl-1-cyclohexen-1-yl)-3-methyl-1,4-pentadien-3-ol, a intermediate for canthaxanthin, from hydroxy-.beta.-ionone.

Preparation of a 1,4-pentadien-3-ol

Novel syntheses of tryptophans

A method for electrochemically alkanoyloxylation of beta-ionone to alkanoyloxy-beta-ionone, an intermediate for canthaxanthin.

Alkanoyloxylation of beta-ionone

Lower alkyl esters of 2-formamido-3(4,5,6 or 7-methyl substituted-3-indolyl)-2-carbalkoxy propionic acid which are useful as intermediates for tryptophane sweetners.

Lower alkyl esters of .alpha.-formamido,.alpha.-carbalkoxy tryptophans

L-3,4-dehydroproline is produced in good yield from D,L-3,4-dehydroproline by resolution via the tartaric acid salt and thermal racemization of the D-3,4-dehydroproline tartaric acid salt containing mother liquors.

Process for L-3,4-dehydroproline

Synthesis of tryptophans

An improved process for the preparation of 6,6-alkylenedioxyalkan-2-ones starting from alkyl vinyl ketones and alkyl acetoacetates is disclosed. The 6,6-alkylenedioxyalkan-2-ones are useful as intermediates in the total synthesis of therapeutically valuable steroids.

Intermediate in the preparation of 6,6-alkylenedioxyalkan-2-ones

Process for the preparation of 6,6-alkylenedioxyalkan-2-ones

2-Lower alkyl-cyclopentan-1,3-diones are prepared in high yield by cyclization of gamma-ketoesters in the presence of a colloidal suspension of an alkali metal primary lower alcoholate.

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Roseland, NJ, United States of America

Urs Oskar Hengartner