Back to results
US 6,271,375 B1Granted
Ortho-metalation process for the synthesis of 2-substituted-1-(tetrazol-5-yl)benzenes
AssigneeZambon Group S.p.A.
InventorsMarco Villa, Pietro Allegrini, Katiuscia Arrighi, Maurizio Paiocchi
Life of this patent
Estimating the term…
Abstract
A process of direct metalation of phenyltetrazoles useful for preparing compounds of formula (II) intermediates for the synthesis of angiotensin II antagonists is described.
Claims11
A process of direct ortho-metalation for the preparation of compounds of formula
- in which
- R is a hydrogen atom, a protective group or a salifying group and X is a halogen atom selected among chlorine, bromine or iodine;
- which comprises the treatment of a compound of formula
- in which R has the above reported meanings;
- with a Grignard compound of formula
- R1MgX (IV)
- in which X has the just reported meanings and R1 is a straight or branched C1-C6 alkyl group or a benzyl group;
- in the presence of a catalytic amount of a secondary amine of formula
- R2-NH-R3 (V)
- in which R2 and R3, the same or different, are branched or cyclic C3-C6 alkyl groups or trialkylsilyl groups having from 1 to 3 carbon atoms in the alkyl moiety or R2 and R3 together with the NH group form an optionally substituted cyclic amine.
7 more elements
Dependencies are inferred from the claim text.