2,3-Dichloromaleic anhydride

Hexafluoro-2,5-dihydrofuran [24849-02-3] is distilled into sulfur trioxide [7446-11-9] at 25°C. Addition of trimethyl borate [121-43-7] initiates a reaction which upon heating and distillation leads to a 53% yield of difluoromaleic anhydride. Dichloromaleic anhydride [1122-17-4] can be prepared with 92% selectivity by oxidation of hexachloro-1,3-butadiene with SO in the presence of iodine-containing molecules (65). Passing vaporized... 

Dichloromaleic anhydride [1122-17-4] M 167.0, m 105-115", 120", 121-121.5". Purified by sublimation in vacuo [Katakis et al. J Chem Soc, Dalton Trans 1491 7986]. It has also been purified by Soxhlet extraction with hexane, recrystd from CHCI3 and sublimed [MS, Relies J Org Chem 37 3630 1972],... 

Dichloromaleic anhydride, Sodium chloride See Dichloromaleic anhydride Sodium chloride, etc. 

One exception to the use of primary phosphines is in the reported syntheses of the catASium M dass of ligands 20 [46-49]. In one report, reaction of the cyclic sulfate with P(TMS)3 yields the TMS-protected secondary phospholane, which could then be reacted with the appropriate 1,2-dichloro spedes [46]. An alternative procedure to the same intermediate involves preparation of 1-phenyl-phospholane via the bismesylate, subsequent lithium-induced P-Ph deavage, and quenching with TMSC1 [49]. The ligand based on 2,3-dichloromaleic anhydride (20a originally referred to as MalPHOS [46]) has been shown to be effective for the chiral reduction of a- and /1-deliydroarnino acid derivatives and itaconate derivatives. 

The heterocyclic acylphosphines (52) and (53) have been prepared by the reaction of phenylbis(trimethylsilyl)phosphine with the acid chlorides derived from phthalic and diphenic acids. The reaction of 2,3-dichloromaleic anhydride or thioanhydride with phenylbis(trimethylsilyl)phosphine gives derivatives of the 1,4-dihydro-p-diphosphorin system (54).45... 

Fluorination of dichloromaleic anhydride proceeds at 300 C to give mainly cyclic products, difluoro lactone (28) and tetrafluoro ether (29) together with the isomeric 2,3-dichlorohexa-fluorobul-2-ene (30) in ratios depending on the reaction time. The lactone 28 is evidently an intermediate in this reaction. 21... 

In another example it has been shown that boron trifluoride is the catalyst of choice to convert dichloromaleic anhydride (9) with sulfur tetrafluoride into 3.4-dichloroperfluoro-2,5-dihy-drofuran (10). In its absence only the formation of a,/i-dichloro->, , -difluoro-y-crotonolactone is observed. 3,4-Dichloroperfluoro-2,5-dihydrothiophene can be prepared in the same manner. 11... 

The reaction between a phenol and dichloromaleic anhydride catalyzed by aluminum chloride gives an aroylacrylic acid, which cyclizes to a chromone on treatment with a weak base (79SC129). However, at higher temperatures an indenone is formed. 

Dichloro-5,7,7,12,14,14-hexamethyl-l, 4,8,1 l-tetraaza-4,11-cyclotetradecadie-neiron(III) perchlorate, 3719 Dichloromaleic anhydride, 1355 f Dichloromethane, 0396... 

G. B. Vermont, P. X. Riccobono and /. Blake The photosensitized reaction of dichloromaleic anhydride with benzene. A novel variation in the photochemistry of maleic anhydride derivatives. J. Amer. chem. Soc. 87, 4024 (1965). 

In another reaction, conducted also in acetic acid, methylmaleic hydrazide (21, R = R2 = H, Ri = Me) has been isolated as the only product.If, however, a mixture of acetic acid and methanol were employed as solvent, citraconic and related anhydrides formed linear dihydrazides of type 23. A new type of reaction product, a A,A -biimide (26), has been established to result when dimethyl- or dichloromaleic anhydride were allowed to react with hydrazine in acetic acid with cooling. 

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