A similar behaviour has since been noticed in other trimethylene derivatives, but the fact that bromine, which usually acts so much more readily than hydrobromic acid on unsaturated compounds,, should be so inert when hydrobromic acid acts readily is one still.
Perkin, junr., in 1883, that ethylene and trimethylene bromides are capable of acting in such a way on sodium acetoacetic ester as to form triand tetramethylene rings.
Propylene, C 3 H 6, may be obtained by passing the vapour of trimethylene through a heated tube (S.
It forms an addition product with acrylic ester, which on heating loses nitrogen and leaves trimethylene dicarboxylic ester.
Pinner, Ber., 1893, 26, p. 2125); and with trimethylene bromide to form a phenyl tetrahydropyrimidine (Pinner).