8.05.2.2.4 Chloroacetic acid complexes
Heating a benzene solution of chloroacetic acid in the presence of [Co(Ox)2] initially gives the red complex [Co(O2CCH2Cl)(Ox)(HOx)] which, if left overnight in the presence of excess acid, forms Violet complex [Co(O2CCH2Cl)(Ox)].85 The structure of these complexes is similar to the dichloroacetic acid complex discussed earlier.
[Co(O2CCH2Cl)2] reacted with tmen in ethanol to give the complex [Co2(μ-OH2)(μ-O2CCH2Cl)2(O2CCH2Cl)2(tmen)2]. 56 The structure of this complex is similar to that of acetate, trichloroacetate, and dichloroacetate complexes, discussed previously. The magnetic susceptibility of the composite was examined between 2 and 80 K and found to have a maximum at 4.8 K and a magnetic moment of 4.8 BM at 80 K.
, 4-dichlorophthalazine and thiosemicarbazide were condensed in DMF to obtain 1,4-bis(thiosemicarbazide) phthalazine 444, which was cyclized with carbon disulfide in the presence of potassium hydroxide to obtain 1,4-bis(3', 5'-dithiol-[1,2,4]triazol-1-yl)phthalazine 445. Compound 445 reacted with monochloric acid in the presence of NaOH to generate 1,4-bis-(1'-thiooxy-6'-oxo-[1,2 ,4]triazolo[3,4-b]-1,3 -Thiazol-2'-yl]phthalazine 446 (Scheme 51) 2001 IJC(B)500. chloroacetic acid

The main application of this type of reaction is the construction of 1,4-benzothiazepines by reaction of (398) type substrates with C single bond C single bond N fragments from appropriate sources. Thus, 2,3-dihydro-1,4-benzothiazepin-5-one (399) can be prepared by a one-step reaction of (398; R = OH) with aziridine. However, the reaction of 2-mercaptoarylketone (398; R = Ph) with 2-bromoethylamine hydrochloride is a two-stage process, first giving (400), which cyclizes in the presence of pyridine to give (401). Reaction of (398; R=OMe) with chloroacetonitrile in the presence of alcohol (R1OH) affords (402). Formation of d-bonds as amide bonds is valuable in the synthesis of dibenzo[b,f]thiazepines 74OPP28