Molecular structures of 4 representative 5-membered
single-ring heterocyclic aromatic compounds (above), and of the parent triazole compounds 1,2,3 and 1,2,4 triazole (below).
Therefore, the present discussion will be limited to monocyclic compounds with 5-membered
They differ in that the 5-membered
thiazolidine ring of penicillin is replaced in the cephalosporins with a 6-membered dihydrothiazine ring.
11) Group G C[H.sub.3] Single-bonded 214 C[H.sub.2] 133 CH< 28 >C< -93 C[H.sub.2]= Double bonded 190 -CH= 111 >CH= 19 -CH=C< 285 >C=C< 222 Phenyl 735 Phenylene o,m,p 658 Napthenyl 1,146 Ring 5-membered
105-115 Ring 6-membered 95-105 Conjugation 20-30 H Variable 80-100 O Ethers 70 CO Ketones 275 COO Esters 310 CN 410 CI Mean 260 CI Single 270 CI Twin (>CC[I.sub.2]) 260 CI Triple (-(CC[I.sub.3]) 250 Br Single 340 I Single 425 C[F.sub.2] n-fluorocarbons 150 C[F.sub.3] 274 S Sulfides 225 SH Thiols 315 ONO Nitrates ~440 N[0.sub.2] Nitro-compounds ~440 P[0.sub.4] Organic phosphates ~500 -38 Table 2--solubility parameters for common polymers (ref.
FA formation by isomerization of pyrene (MW 202) is unlikely in light of the high activation energy needed to form a 5-membered
ring from a 6-membered ring, and in light of Scott and Roelofs' (29) report of FA equilibrium with two other 5-membered
ring PAHs, acephenanthrylene and acenanthrylene, but not pyrene, in experimental studies of FA pyrolysis at 920, 1,000, and 1,115 [degrees] C.
Compound 3 presents interesting structural features with 4- and 5-membered
fused rings with the piperidinedione ring at almost right angle with the pyrrolidine ring containing dihedral angles of 67.6[degrees] and 73.9[degrees] for the cyclobutane and 2,6-dioxopiperidine rings, respectively.
The spectra of Diacerein showed characteristic peaks at 3300 cm-1 (COOH) and 760 cm-1 (m- substituted benzene), Span 60 at 2916 cm-1 (OH), Span 80 at 1740 cm-1 (5- membered ring), Span 85 at 1643 cm-1 (ketone with 5-membered ring), Tween 20 at 1734 cm-1 (5-membered ring) and Tween 80 at 3488 cm-1 (OH).
###Span 60###2916.75 cm-1,1467.56 cm-1, 1734.65 cm-1, 1000to1200 cm-1###OH, CH3, Cyclic 5-membered ring, aliphatic chain
###Span 80###2412.63 cm-1, 2923 cm-1,1740 cm-1, 1463.49 cm-1###Aromatic ring, OH, 5-membered ring, CH3
Balsamo, Synthesis and biological evaluation of 5-membered
spiro heterocycle-benzopyran derivatives against myocardial ischemia, Eur.