Lonza Ag

Christine Bernegger

Walter Brieden

Eva Maria Urban

Laurent Duc

Olwen M Birch

Yves Guggisberg

Frank Brux

Pierre Bossard

Colm O'Murchu

Kay-Sara Etter

John Gordon

Kurt Burgdorf

Knut Burgdorf

A process for the preparation of a racemic or optically active compound of the formula

Process for the preparation of a racemic or optically active 4-(hydroxymethyl)-2-cyclopentene derivative

A novel process for the preparation of (1S, 4R)- or (1R, 4S)-4-(2-amino-6-chloro-9H-purin-9-yl)-2 -cyclopentene-1-methanol of the formula

Process for the preparation of an enantiomer of a (1R, 4S) or (1S, 4R)-1-amino-4-(hydroxymethyl)-2-cyclopentene derivative

A novel process for the preparation of (1S,4R)- or (1R,4S)-4-(2-amino-6-chloro-9H-purin-9-yl)-2-cyclo-pentene-1-methanol of the formulae ##STR1## is described. This entails in the first stage (.+-.)-2-aza-bicyclo[2.2.1]hept-5-en-3-one of the formula ##STR2## being acylated to give a (.+-.)-2-azabicyclo[2.2.1]hept-5-en-3-one derivative of the general formula ##STR3## in which R.sup.1 denotes C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, aryl or aryloxy, the latter being reduced in the second stage to give a cyclopentene derivative of the general formula ##STR4## in which R.sup.1 has the stated meaning, the latter then being converted in the third stage biotechnologically into the (1R,4S)- or (1S,4R)-1-amino-4-(hydroxymethyl)-2-cyclopentene of the formula ##STR5## the latter being converted in the fourth stage with N-(2-amino-4,6-dichloro-5-pyrimidinyl)formamide of the formula ##STR6## into the (1S,4R)- or (1R,4S)-4-[(2-amino-6-chloro-5-formamido-4-pyrimidinyl)amino]-2-cyclopente ne-1-methanol of the formulae ##STR7## and the latter being cyclized in the fifth stage in a known manner to the final product of the formula I or II.

Process for the preparation of (1S,4R)-  or (1R,4S)-

A novel process for the preparation of (1S,4R)- or (1R,4S)-4-(2-amino-6-chloro-9H-purin-9-yl)-2-cyclopentene-1-methanol of the formulae ##STR1## is described. This entails in the first stage (.+-.)-2-azabicyclo[2.2.1]hept-5-en-3-one of the formula ##STR2## being acylated to give a (.+-.)-2-azabicyclo[2.2.1]hept-5-en-3-one derivative of the general formula ##STR3## in which R.sup.1 denotes C.sub.1-4 -alkyl, C.sub.1-4 -alkoxy, aryl or aryloxy, the latter being reduced in the second stage to give a cyclopentene derivative of the general formula ##STR4## in which R.sup.1 has the stated meaning, the latter then being converted in the third stage biotechnologically into the (1R,4S)- or (1S,4R)-1-amino-4-(hydroxymethyl)-2-cyclopentene of the formula ##STR5## the latter being converted in the fourth stage with N-(2-amino-4,6-dichloro-5-pyrimidinyl)formamide of the formula ##STR6## into the (1S,4R)- or (1R,4S)-4-[(2-amino-6-chloro-5-formamido-4-pyrimidinyl)amino]-2-cyclopente ne-1-methanol of the formulae ##STR7## and the latter being cyclized in the fifth stage in a known manner to the final product of the formula I or II.

Enantiomer compositions of

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Münster, Switzerland

Christine Bernegger