Hoffmann-la Roche Inc.

Willy Leimgruber

Manfred Weigele

Donald H Valentine, Jr

Andrew D Batcho

Emanuel Grunberg

Roy Cleeland, Jr

John William Scott

Urs Oskar Hengartner

Leo Berger

Fausto Eugenio Schenker

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

Novel syntheses of tryptophans

Compounds of the formula ##STR1## wherein R.sub.1 is lower alkyl or phenyl lower alkyl; R.sub.2 is phenyl or substituted phenyl; and R.sub.3 is substituted or unsubstituted phenyl, naphthyl or indolyl; are fluorogenic reagents which react with primary amino groups to form fluorophors. The above compounds are useful for fluorescent labeling of materials of biological importance.

Fluorogenic materials and labeling techniques

A process is disclosed for preparing racemic and optically pure tryptophans through novel intermediates.

Synthesis of tryptophans

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

A multi-step process for the preparation of alpha,beta-unsaturated aliphatic aldehydes such as citral by first reacting an allylic alcohol with a butadienyl ether, or a corresponding acrolein derivative or its acetal, including novel intermediates in this process.

Process for the preparation of aldehydes

Compounds of the formula ##STR1## wherein R.sub.1 is lower alkyl or phenyl lower alkyl; R.sub.2 is phenyl or substituted phenyl; and R.sub.3 is substituted or unsubstituted phenyl, naphthyl or indolyl; Are fluorogenic reagents which react with primary amino groups to form fluorophors. The above compounds are useful for fluorescent labeling of materials of biological importance.

1-Dimethylamino-2,4-diphenyl-1-butene-3,4-dione

Compounds of the formula ##STR1## wherein R.sub.1 is lower alkyl or phenyl lower alkyl: R.sub.2 is phenyl or substituted phenyl: and R.sub.3 is substituted or unsubstituted phenyl, naphthyl or indolyl; Are fluorogenic reagents which react with primary amino groups to form fluorophors. The above compounds are useful for fluorescent labeling of materials of biological importance.

Certain 2-hydroxy-2,4-diaryl-3-furanones

Compounds of the formula ##STR1## wherein R.sub.1 is lower alkyl or phenyl lower alkyl: R.sub.2 is phenyl or substituted phenyl; and R.sub.3 is substituted or unsubstituted phenyl, naphthyl or indolyl; Are fluorogenic reagents which react with primary amino groups to form fluorophors. The above compounds are useful for fluorescent labeling of materials of biological importance.

Ortho-nitrotoluenes are condensed with formamide acetals to yield the corresponding otho-nitro-.beta.-aminestyrenes which undergo cyclization upon reduction to yield indoles.

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Montclair, NJ, United States of America

Willy Leimgruber