Benzoxathiole dioxide

There have been a few reports of new [4+2] cycloaddition reactions including reaction of the 2-alkylidene-l,3-benzoxathiole dioxides 149, formed as shown in Section 4.10.5.1, with diene 150 to give products 151 (Equation 39), and this is how compound 57 was prepared <1996AP361>. The chiral 4,5-diaryl-2-methylene-l,3-dioxolanes 152 have been reacted both with formylcyclohexenones 153 (Equation 40) and 2-acetylaminomethylene-l,3-diones 154 (Equation 41) to give the corresponding hetero-Diels-Alder adducts <1999T12907, 2003T341>. 

H-2,l-Benzoxathiol-3-ylidene)bis[2-bromo-6-methylphenol] S,S-dioxide, 9CI. 3,3-Bis 3-bromo-4-hydroxy-5-methylphenyl)-3 i-2,l-benzoxathiole -dioxide. 5, 5"-Dibromo-o-cresolsulfonephthalein [115-40-2]... 

C3OS 0 S — — — 3,3-Diphenyl-1,2-oxathiolane 2,2-dioxide 5H-l,2-benzoxathiole 2,2-dioxide... 

Morpholino-ethyl isocyanide. 5-Nitro-[3H]-l,2,-benzoxathiole S,S-dioxide (5-Nitropyridyl)-diphcnyl phosphinate. Tetrahydrothiazole-2-thione. 

DFT theory at the B3LYP/6-31G(d,p) level was used to investigate the Diels-Alder reactions of o-quinone methides with various ethenes. Calculations show that solvent decreases the activation energy and increase the asynchronicity.116 The Diels-Alder reaction of ortho-quinone methides derived from 3//-1,2-benzoxathiole 2,3-dioxides with maleimides produces chroman 2,3-dicarboxylic acid derivatives.117... 

Diaryl-3//-2,l-benzoxathiole 1-oxides react with hydrazine to give high yields of 9-aryl-9//-thioxanthene 10,10-dioxides. It is proposed that the role of the hydrazine is to initiate cleavage of the O-C bond which is followed by attack of S on the adjacent aromatic ring (Equation 124) <1998H(49)143>. 

C3OS 0 s C c c 5-Methyl-3-phenyl-l,2-oxathiolane 2,2-dioxideat 5/7-1,2-benzoxathiol 2,2-dioxide... 

Spiro(37/-2,l-benzoxathiol-3-one)-l,l -37/-2-methyl-l,3,2-benzodithiazole 3,3-dioxide 179 is readily available from sulfoxide 178 under mild reaction conditions, and optimal 86% yield of spiro-A4-sulfane 179 was achieved after 10-15 min at room temperature. Harsher reaction conditions, that is, 3h at reflux, lead to ring-enlargement product, dibenzodithiazocine 180, in 89% yield (Scheme 48 <1995CC1069>). 

Thermolysis of the benzoxathiole V,V-dioxides 45 provides a convenient method for generation of n-quinone methides for cycloaddition. The reaction was performed in boiling n-dichlorobenzene at 180 °C with a variety of substituted maleimides 46 to give the adducts 47 (Equation 1) <2005T8419>. 

The crystal structures of the 1,3-oxathiolane derivatives 50 and 51 have been reported <2005EJ01613>. The stereoselectivity of the reaction of benzo-l,3-dithiole A-oxide with various electrophiles has been examined, and the X-ray structures of a number of different diastereomeric products including 52-55 have been determined <2001T10365>. Finally, X-ray diffraction studies have been reported for substituted benzoxathiole 1,1-dioxides 56 and 57 <1996AP361>. 

There has been only one significant new report of reactivity of this type. Deprotonation at C-2 of the substituted benzoxathiole 1,1-dioxide 88 followed by addition of a silyl chloride gave 89. This was then deprotonated again followed by addition of acetaldehyde to furnish the alkene 90 via a Peterson reaction (Scheme 1) <1996AP361>. 

In a related study, the spiro thiadiazoline 212, formed by reaction of 208 with CHzNz, reacts with methyl pymvate or its trifluoro analogue to give oxathiolane products 213 resulting from thiocarbonyl ylide cycloaddition (Equation 74) <1996HCA1537>. Reaction of fluorobenzoquinone with chloromethanesulfmic acid affords the benzoxathiole A,A-dioxide 214 (Equation 75) <1996AP361>. 

Further properties of the parent 1,2-oxathiolane (5) have been described and representative 2,1-benzoxathiol-3-ones (6) have been prepared. The majority of work has, however, been on 5-oxidized derivatives including 5/f-l,2-oxathiole 2-oxides (7) and 2,2-dioxides (8), and their benzo derivatives... 

The cyclic sulfites (104) undergo ring contraction upon treatment with BF3 EtjO to give the 1,2-oxathiolane 2,2-dioxides (105) (Equation (19)) <93TL3667>. Access to the 2,l-benzoxathiol-3-one... 

Bromcresol purple Bromocresol purple EINECS 204-087-8 NSC 374134 Phenol, 4,4 -(3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-methyl-, S,S-dioxide Phenol, 4,4 - 1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-methyl. An add-base indicator. Crystals mp = 241,5" irritant practically insoluble in H2O, soluble in EtOH. 

Beilstein Handbook Reference) BCG BRN 0372527 Bromcresol green EINECS 200-972-8 NSC 7817 Phenol, 4,4 - 1,1-dioxido-3H-2,1-benz-oxathiol-3-ylidene)bis(2,6-dibromo-3-methyl- Phenol, 4,4 -(3H-2,1-benzoxathiol-3-ylidene)bis(2,6-dibromo-3-methyl-, S,S-dioxide o-Toluenesulfonic acid, o-hydroxy-, gamma-sultone Tetrabromo-m-cresolphthalein sulibne. An acid indicator pH 3.8 (yellow)-5.4 (blue-green). Red-yellow crystals mp = 218.5° Xjn = 211, 278, 338,426 nm (e 54100. 8500, 7550, 17100 MeOH), 312, 394, 620 nm (s 13300, 8520, 40100 MeOH/KOH) insoluble in H2O, soluble in organic solvents. Lancaster Synthesis Co. Mallinckrodt Inc. Sigma-Aldrich Fine Chem. 

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