The synthesis of new diastereomers of (4S,8aS)- and (4R,8aS)-4-phenyl-perhydropyrrole[1,2-a]pyrazine-1,3-dione

The Solid-State Structures of Cyclic NH Carboximides

“…In compound 265 [222], the imide NH of one molecule is hydrogen bonded to the imide CO of another molecule, but the reciprocal interaction does not occur, resulting in a D type interaction. Compounds 267 [224] and 268 [225] exist as simple hydrogen-bonded ribbons of pattern B. Compound 269 [226] shows two crystal forms both as C(7) chains with the imide NH bonded to the remote CO of the pyrrolidinone ring in pattern F.…”

“…Compound 275 [228] (Figure 77), which is the racemic form of the pure enantiomer 271, forms R Five structures, compounds 270 [227], 271 [228], 272 [229], 273 [229] and 274 [230] (Figure 76) are bis imides that hydrogen bond to give a doubly linked chain of pattern H with respective designations C [222], the imide NH of one molecule is hydrogen bonded to the imide CO of another molecule, but the reciprocal interaction does not occur, resulting in a D type interaction. Compounds 267 [224] and 268 [225] exist as simple hydrogen-bonded ribbons of pattern B. Compound 269 [226] shows two crystal forms both as C (7) chains with the imide NH bonded to the remote CO of the pyrrolidinone ring in pattern F. Five structures, compounds 270 [227], 271 [228], 272 [229], 273 [229] and 274 [230] (Figure 76) are bis imides that hydrogen bond to give a doubly linked chain of pattern H with respective designations C Three structures display more complex forms of hydrogen bonding.…”

Chirality as an Important Factor for the Development of New Antiepileptic Drugs

“…In the first step, l ‐proline ( 81 ) was subjected to esterification resulting in the respective methyl ester, which then underwent ammonolysis to give amide derivative 82 . In the next step 82 was condensed with ( R )‐2‐(4‐toluenesulfonyloxy)phenylacetic acid methyl ester (obtained according to a method described elsewhere), resulting in intermediate 83 . Finally, the piperazine ring was closed under basic conditions in ethanol, to yield the final compound (4 S ,8a S )‐ 3 .…”

Synthesis of a New Scaffold: the 7H,8H-Pyrimido[1,6-b]pyridazin-6,8-dione Nucleus

“…Moreover, it also affects the lipophility of the ligand, which in turn has a significant effect on selectivity of the ligand to 5-HT 1A receptor, with respect to other receptors such as 5-HT 2A or α 1 [2,7,9]. Our earlier investigations also dealt with the preparation of new heterocyclic systems, such as for instance the derivatives of pyrido [1,2-c]pyrimidine and pyrrole [1,2-a]pyrazine, which have the afore-mentioned grouping [11][12][13]. We have now focused our studies on a little known pyrimido [1,6-b]pyridazine system, the derivatives of which had already been described by Bemis et al Our investigations were concerned with Kinase p38 inhibitors which possess antitumor activity [14].…”