Reference

Synthesis of a eutectic mixture of tetra- and hexahydrophthalic anhydrides as liquid curing agent for epoxy resins

Synthesis of a eutectic mixture of tetra- and hexahydrophthalic anhydrides as liquid curing agent for epoxy resins. Rokicki, Gabriel; Kozlowski, Antoni; Kielkiewicz, Jedrzej (Inst. Technol. Tworzyw Sztuczn., Politech. Warszawska, Warsaw, Pol.). Przem. Chem., 65(12), 666-9 (Polish) 1986. CODEN: PRCHAB. ISSN: 0033-2496. 4325-56-8 and 106-99-0 which are cas registry numbers are also used here. DOCUMENT TYPE: Journal CA Section: 37 (Plastics Manufacture and Processing) Hydrogenation of cis-D4-tetrahydrophthalic anhydride (I) [935-79-5] in H over a Ni catalyst at 3150° led to formation of hexahydrophthalic anhydride (II) [85-42-7] and simultaneously to isomerization of I to cis-D1 [2426-02-0] and cis-D3-tetrahydrophthalic anhydride [4325-56-8]. The amt. of II increased linearly with increasing amt. of H in the reaction system. The highest isomerization rate was obsd. at the onset of the process. The end product contained II ~70, I ~8-10, and the other 2 isomers ~20-22%. A rapid catalyst deactivation was obsd. at e200°. The optimum reaction temp. was 160-170°. .

Reversible acylation and inhibition of aggregation of platelets by substituted maleic anhydrides

Reversible acylation and inhibition of aggregation of platelets by substituted maleic anhydrides. Walder, Joseph A.; Hyman, Bradley T.; Heller, Michael J.; Shishido, Roxanne Y.; Klotz, Irving M. (Dep. Biochem. Mol. Biol., Northwest. Univ., Evanston, Ill., USA). Mol. Pharmacol., 13(3), 407-14 (English) 1977. CODEN: MOPMA3. DOCUMENT TYPE: Journal CA Section: 1 (Pharmacodynamics) The antiprostaglandin action of aspirin [50-78-2] due to the acetylation of the enzyme prostaglandin synthetase [9055-65-6] was manifested by inhibition of the so-called release reaction and consequent abolition of secondary-phase aggregation. The maleic anhydrides, a series of reversible acylating agents, produced the aspirin-type defect in platelet aggregation. The antiplatelet effect of aspirin was irreversible. With 2,3-dimethylmaleic anhydride [766-39-2], however, the antiplatelet effect disappeared in .apprxeq.80 min at 25.degree.. Hence the persistence of the lesion when caused by aspirin results from the stability of the acetyl linkage formed in its reaction with prostaglandin synthetase. This suggests that the modification occurs at either a lysine or an NH2-terminal amino group. That such is the case was confirmed by the observation that 3,4,5,6-tetrahydrophthalic anhydride [2426-02-0] and 2,3-dimethylmaleic anhydride, both amino-sp. acylating agents, were able to produce the aspirin-type lesion. Thus, upon deacylation, prostaglandin synthetase regains its activity and platelet function returns to normal. Accordingly, it may be possible to develop a clin. acceptable, reversible acylating agent with short-acting, aspirin-like effects.