Abstract: Process for the preparation of polyhydantoins or polyparabanic acids, characterized in that bis- or polyglycine derivatives or bis- or poly-monoamidooxalic acid derivatives are heated to temperatures of 20.degree. to 250.degree. C with di- or polyiso(thio)cyanate derivatives without solvents and the highly fluid melt which has a melt viscosity of at the most 40,000 m.Pa.s. is optionally subjected to a shaping process and is polycondensed by adjustment to the reaction of 80.degree. to 700.degree. C.

Abstract: Cyclic aminals of aromatic heterocyclic compounds useful in the dyestuffs, pharmaceutical and pesticides industries, are prepared by reacting aromatic heterocyclic compounds containing at least one NH-group in a ring with a tetra-aminoethylene.The cyclic aminals produced have the formula ##STR1## wherein X.sup.5, X.sup.6, X.sup.7 and X.sup.8 are the same or different and areA. nitrogen; orB.X.sup.5 is C - R.sup.3 and/orX.sup.6 is C - R.sup.4 and/orX.sup.7 is C - R.sup.5 and/orX.sup.8 is C - R.sup.6,whereinR.sup.3, r.sup.4, r.sup.5 and R.sup.6 are the same or different and are selected from the group of hydrogen, optionally substituted aliphatic, aromatic, heterocyclic or araliphatic, and any other radical which does not react with tetra-aminoethylene; or two adjacent radicals together with the carbon atoms substituted thereby can form a fused ring; orC. the group (Z): ##STR2## wherein R.sup.1 and R.sup.2 are as defined in claim 1; andD. at least one of the radicals X.sup.5, X.sup.6, X.sup.7 and X.sup.

Abstract: Novel compounds which upon heating are converted into the corresponding phenol which is a catalyst for the trimerization of compounds having isocyanato groups to form isocyanurates have the formula: ##SPC1##In whichn represents an integer of from 1 to 4A represents an aromatic hydrocarbon group obtained by removing the NCO group from a monomeric aromatic monoisocyanate containing 6 - 14 carbon atoms,R.sub.1 and R.sub.2 may be the same or different and represent a C.sub.1 to C.sub.6 alkyl group or a polymethylene chain containing 4 to 8 carbon atoms which together with a nitrogen atom form a heterocyclic ring,R.sub.3 may be hydrogen, chlorine, bromine or a C.sub.1 - C.sub.18 -alkyl group.

Abstract: Reaction products containing free isocyanato groups are produced by reacting ketimines with polyisocyanates.

Abstract: A process for preparing compounds which contain hydantoin groups, which is characterized in that compounds which contain isocyanate or isothiocyanate groups are reacted with compounds which contain an .alpha.-halocarboxylic acid group or derivatives thereof at least once in the molecule.

Abstract: A process for preparing compounds containing hydantoin groups, wherein compounds which contain isocyanate or isothiocyanate groups are reacted with compounds which contain at least one, preferably two .alpha.-halocarboxylic acid amide groups or one .alpha., .alpha.'-dihalodicarboxylic acid diamide group.