34 1125 1126 and the compound b obtained is reacted with an alkyllithium such as butyllithium in an aprotic solvent such as tetrahydrofuran at a temperature of between 50 u00b0 c and 20 u00b0 c an organolithium derivative is obtained and is reacted with trialkyl borate in a solvent such as tetrahydrofuran an alkyl benzeneboranate is obtained which is subjected to a hydrolysis reaction in a fourth step deprotection of the tetrazole group of the compounds of general formula vii is carried out by heating in a strong acid such as for example aqueous hydrobromic acid hydrobromic acid dissolved in acetic acid sulphuric acid or acetic acid in the presence of boron trifluoride etherate to obtain the compounds of general formula i the invention includes a compound represented by formula v str7 in which r 1 and r 2 are as defined above the example which follows illustrates the invention the analyses confirm the structure of the products obtained 5 16 g of potassium 1 1 dimethylethylate and 60 ml of dimethylformamide are introduced into a 250 ml three necked round bottomed flask maintained under nitrogen the mixture is cooled to 4 u00b0 5 u00b0 c there follows the dropwise addition in the course of 45 minutes of a solution of 7 28 g 46 mmol of methyl oxoheptanoate in 18 ml of dimethylformamide and then 8 7 g of lithium bromide after 15 minutes 39 stirring a solution of 10 g 40 mmol of 1.