There is provided a process for the production a compound of general formula I: ##STR00001## wherein A, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 have meanings given in the description, which process comprises the reaction of a compound of formula II, ##STR00002## wherein R.sup.x is a group substitutable by an aminopyrazole, with a compound of general formula III ##STR00003##

There is provided a process for the production a compound of general formula I: ##STR1## wherein A, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 have meanings given in the description, which process comprises the reaction of a compound of formula II, ##STR2## wherein R.sup.x is a group substitutable by an aminopyrazole, with a compound of general formula III ##STR3##

A process for the preparation of a compound of formula (I): ##STR1## which comprises cyclization of a compound of formula (II): ##STR2##

A process is provided for the preparation of a compound of formulae (IA) (sidenafil) and (IB) ##STR1## comprising reacting a compound of formula (IIA) and (IIB) respectively in the presence of .sup.-- OR, wherein R in the case of formation of compound (IA) is CH.sub.2 CH.sub.3 and R in the case of formation of compound (IB) is CH.sub.2 CH.sub.2 CH.sub.3, where X is a leaving group: ##STR2##

The present invention relates to a crystalline, .alpha.-polymorphic form of a compound of formula (I) and to processes for the preparation of, to intermediates used in the preparation of, to compositions containing and to uses of, the .alpha.-polymorphic form. ##STR1##

A method of reducing the formation of silicon crystal defects due to extrinsic stresses in an integrated circuit chip. The source of such extrinsic stresses may be filling trenches with polycrystalline silicon or oxide, silicides, forming silicon nitride spacers or liners, or during oxide birds-beak formation, or at numerous other processing points. At an appropriate point, as each sensitive feature is defined or formed, carbon co-implanted into the silicon wafer at or near the feature.

A process for the preparation of a compound of formula (I): ##STR1## which comprises cyclization of a compound of formula (II): ##STR2##

2-(5H-dibenzo[a,d]cyclohepten-5-on-2-yl)acetic, propionic and butyric acids, and esters and salts thereof, are prepared by solvolysis of nitrile or amide intermediates, or of ketal-protected nitrile, amide, acid, ester or salt intermediates.

Compounds of the formula ##STR1## wherein R is hydrogen or methyl; R.sup.1 is hydrogen, C.sub.1 to C.sub.8 linear or branched alkyl or C.sub.1 to C.sub.8 linear or branched alkanoyl; X is oxygen or sulfur; R.sup.2 is selected from the group hydrogen, C.sub.1 to C.sub.18 linear or branched alkyl and the radicals --(CH.sub.2).sub.n --NR.sup.3 R.sup.4, --CH.sub.2 --CH(OH)--CH.sub.2 --OH or a ketal thereof formed from the aldehyde or ketone R.sup.5 R.sup.6 CO, wherein R.sup.3 and R.sup.4 are each in...

2-(5H-dibenzo[a,d]cyclohepten-5-on-2-yl) acetic, propionic and butyric acids, and esters and salts thereof, are prepared by solvolysis of nitrile or amide intermediates, or of ketal-protected nitrile, amide, acid, ester or salt intermediates.