Spiro dioxide

Allenes 6 also react with peracids allene oxides 7 are formed, or even a spiro dioxide 8 can be obtained by reaction with a second equivalent of peracid ... 

Simple allenes (209) react with dimethyldioxirane (200) to give the corresponding spiro-dioxides 210 in instances where diastereoisomeric spiro-dioxides are possible, there is usually an acceptable stereochemical preference for epoxidation to occur anti to the alkyl substituents324,325. Allenic alcohol 211 yields the highly functionalized tetrahydro-furan 212 and tetrahydropyran derivatives by intramolecular nucleophilic addition of the hydroxy group to an intermediate allene diepoxide324. 

Spiro dioxide A compound that contains two epoxide groups that share a common carbon atom, which is bonded in a spiro manner. 

Singlet phenylnitrene, and hence /V,A -diethyl-3//-azcpin-2-amines, e. g. 102, can be generated by the thermolysis of A,-phenyl-Af,<9-bis(trimcthylsi]yl)hydroxylamine (100) in the presence of dialkylamines the reaction fails, however, with arylamines.210 Photofragmentation of the spiro oxaziridine 101 in diethylamine solution also produces the 3//-azepine 102,2,1 and an oxaziridine intermediate is probably involved in the formation, in low yield (1 %), of azepine 102 by the photolysis of A/,A( -diarylbenzoquinonc diimine A/,A/ -dioxides in benzene/die-thylamine solution.212... 

Employing a C2 symmetry in the case of the thiirene 1-dioxide and remembering that the spiro-operator that mixes the fragment orbitals gives nonzero matrix elements only if these orbitals are symmetric to the C2 operation53, the net result is stabilizing. On the other hand, thiirene 1-oxide suffers a homoconjugative destabilization. 

The HEPT and TIBO derivatives were discovered as the result of a systematic evaluation for anti-HIV activity in cell culture. They were later found to achieve their anti-HIV-1 activity through an interaction with the HIV-1 RT. In contrast, nevirapine, pyridinone, and BHAP emerged from a screening program for HIV-1 RT inhibitors. The anti-HIV-1 activity of these compounds was subsequently confirmed in cell culture. Like the HEPT and TIBO derivatives, the 2, 5 -bis-0-(tert-butyldimethylsilyl)-3 -spiro-5" -(4" -amino-1", 2" -oxathiole-2", 2" -dioxide)-pyrimidine (TS AO) derivatives (Fig. 9) [65,66] and a-anilinophenylacetamides (a-APA) (Fig. 10) [67] were discovered through the evaluation of their anti-HIV activity in cell culture. Subsequently, they were found to act as specific inhibitors of HIV-1 RT. 

Figure 9 2, 5 -Bis-0-(ferf-butyldimethylsilyl)-3 -spiro-5"-(4"-amino-1",2"-oxa-thiole-2",2"-dioxide)pyrimidine (TSAO) derivatives TSAO-T, TSAO-m3T, and TSAO-e3T.

Balzarini J, Perez-Perez M-J, San-Felix A, Schols D, Perno C-F, Vandamme A-M, Camarasa M-J, De Clercq E. 2, 5 -Bis-0-(tert-Butyldimethylsilyl)-3 -spiro- 5" -(4" -amino-1", 2" -oxathiole-2", 2" -dioxide)pyrimidine (TSAO) nucleoside analogues highly selective inhibitors of human immunodeficiency virus type 1 that are targeted at the viral reverse transcriptase. Proc Natl Acad Sci USA 1992 89 4392-4396. 

Balzarini J, Velazquez S, San-Felix A, Karlsson A, Perez-Perez M-J, Camarasa M-J, De Clercq E. Human immunodeficiency virus type 1-specific [2, 5 -bis-0-(tert-butyldimethylsilyl)-(i-D-ribofuranosyl]-3 -spiro-5"-(4"-ami-no-1",2"- oxathiole-2",2"-dioxide)-purine analogues show a resistance spectrum that is different from that of the human immunodeficiency virus type 1 -specific non-nucleoside analogues. Mol Pharmacol 1993 43 109-114. 

The three-component reaction between isatin 432a, a-aminoacids 433 (proline and thioproline) and dipolarophiles in methanol/water medium was carried out by heating at 90 °C to afford the pyrrolidine-2-spiro-3 -(2-oxindoles) 51. The first step of the reaction is the formation of oxazlidinones 448. Loss of carbon dioxide from oxazolidinone proceeds via a stereospecific 1,3-cycloreversion to produce the formation of oxazolidinones almost exclusively with /razw-stereoselectivity. This /f-azomethine ylide undergo 1,3-dipolar cycloaddition with dipolarophiles to yield the pyrrohdinc-2-r/ V -3-(2-oxindolcs) 51. (Scheme 101) <2004EJ0413>. 

Only structures pertaining to the saturated 1,2-oxathiane 2,2-dioxides have been published. The preferred chair conformer is preserved in both polycyclic <1989AGE202, 1998CEJ1480, 1996CC431, 1994JOC3687> and spiro derivatives <1998EJO2073> with the sulfone oxygens in pseudoaxial and pseudoequatorial orientations. 

Jonckheere H, Taymans J-M, Balzarini J, Velazquez S, Camarasa M-J, Desmyter J, et al. Resistance. of HIV-1 reverse transcriptase against [2,5,-bis-0-(tert-butyldimethylsilyl)-3 -spiro-5"-(4"-amino-l",2"-oxathiole-2 ,2 -dioxide)] (TSAO) derivatives is determined by the mutation Glu138->Lys on the p51 subunit. JBiol Chem 1994 269 25255-25258. 

When 151 is caused to react with terf-butyl chloride, a coupling occurs in high yield [Eq. (99)] the substitution seems neither to be an SN1 nor an SN2 reaction but was suggested to occur via an initial electron transfer from 151 to f-BuCl, followed by coupling of the two radicals [Eq. (99)].37 Anion 151 also reacts with carbon dioxide, forming a spiro derivative of malonic acid. 

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