Abstract: The present invention relates to new 1-.beta.-methyl-2-thiolic carbapenem derivatives represented by the following general formula (I) and producing method thereof. ##STR1## The above-mentioned compound is very stable against DHP-1 enzyme due to effective shielding of carbapenem ring structually and is highly effective in both gram-positive and gram-negative microorganism, especially has a remarkable effect on the Pseudomonas aeruginosa known as a disease germ having strong resistance.

Abstract: This invention relates to the process for producing ortho-isopropylated phenol derivatives having following general formula (VIII). ##STR1## (in the above formula, R.sub.1 is a hydrogen or a low alkyl group of C.sub.1 -C.sub.4)A process for producing ortho-isopropylated phenol derivatives (VIII) of the present invention is characterized by obtaining position isomer desired by means of Claisen rearrangement of phenyl allyl ether without catalyst in atmosphere, and then obtaining only one isomer by oxidation and reduction of the above-obtained position isomer. According to the present invention, ortho-alkylated phenol derivatives (VIII) having high purity at low temperature and low pressure can be prepared without producing a by-product and requirement of the complicated separation procedure.