Bis dichloromethane

Figure 9. Crystal packing diagram of the complex 59 (bis-dichloromethane solvate), showing the centrosymmetric arrangement of the complexes (solvent omitted) and the ir-stacking interactions [139]...

C5iHftoClFeNeO, Bis(imidazole)-a,/3,7,6-tetraphenylporphinatoiron(111) chloride methanol solvate, 38B, 511 C5 2Cl3FeN60, Nitrosyl-a,, 7,6-tetraphenylporphinato(4-methyl-piperidine) iron (11) chloroform solvate, 43B, 638 C52Cl3MnN60, Nitrosyl-a,, 7,6-tetraphenylporphinato(4-methyl-piper idine )manganese chloroform solvate, 40B, 471 C52H32CI1oNaOeRe2Sb, Bis(tricarbonylrhenium)-M tetraphenylporphyrin hexachloroantimonate bis(dichloromethane) solvate, 43B, 638 C52H3gClCoNg, Chloro-a,, 7,6-tetraphenylporphinato(pyridine)cobalt-(III) benzene solvate, 41B, 574... 

CygHg4Cl402P4Rh2, Tetrakis(triphenyIphosphine) di /z carbonyl dirhod ium(O) - bis(dichloromethane) solvate, 39B, 875 CygHg8Cl202P4Rh2, Bis(triphenyIphosphine)rhodium(I) chloride dimer -ethyl acetate, 44B, 1088... 

Recently Desimoni et used the same bis(oxazoline) ligand in the magnesium(II) catalysed Diels-Alder reaction of the N-acyloxazolidinone depicted in Scheme 3.4. In dichloromethane a modest preference was observed for the formation of the S-enantiomer. Interestingly, upon addition of two equivalents of water, the R-enantiomer was obtained in excess. This remarkable observation was interpreted in terms of a change from tetrahedral to octahedral coordination upon the introduction of the strongly coordinating water molecules. 

From their structures, it appears that the hydrolytic stability of macrocyclic lactones must necessarily be inferior to macrocyclic polyethers. Ease of synthesis of the cyclic esters is therefore one of the aspects which commend them to interest. It is probably for this reason that such lactones have not been made more often by the interesting approach of Kdgel and Schroder . These workers report the ozonolysis of dibenzo-18-crown-6 in a mixture of methanol and dichloromethane at —20°. Reduction of the ozon-ide at —75° using dimethylsulfide followed by warming and addition of acetone led to formation of 6 in 14% yield. The bis-oxalate had mp 164—165° from acetone, very similar to that of the starting crown. The transformation is illustrated below in Eq. (5.9). 

Additional dipping in a 0.001% solution of dansyl semipiperazide or bis-dansyl piperazide in dichloromethane — liquid paraffin (75 -F 25) stabilized the color of the chromatogram for a period of months. 

It is noteworthy that pyridine does not react at atmospheric pressure with dichloromethane to yield salts such as 7a (Scheme 2). Applying higher pressures resulted in A/V -methylene-bis(pyridinium) dichloride (8a) (86T601). 

We therefore prepared a new chiral ligand, (l ,J )-isopropylidene-2,2 -bis[4-(o-hy-droxybenzyl)oxazoline)], hereafter designated J ,J -BOX/o-HOBn. To our delight, the copper(II) complex catalyst prepared from J ,J -BOX/o-HOBn ligand and Cu(OTf)2 was quite effective (Scheme 7.45). Especially, the reaction of O-benzylhydroxylamine with l-crotonoyl-3-isopropyl-2-imidazolidinone in dichloromethane (0.15 m) at -40°C in the presence of J ,J -BOX/o-HOBn-Cu(OTf)2 (10 mol%) provided the maximum enantioselectivity of 94% ee. 

A similar irradiation of imide 9 in acetonitrile gives a mixture of ethyl 4,5-bis(ethoxy-carbonylamino)-l//-l,2-diazepine-l-carboxylate (10) and the isomeric ethyl 5,6-bis(ethoxycar-bonylamino)-l/f-l,2-diazepine-l-carboxylate (11) in the ratio 6 1. In contrast, when the irradiation is carried out in dichloromethane, the ratio is reversed to 1 2.5.81... 

Tetrabutylammonium [bismuth(III) bis(phthalocyanine)] undergoes a one-electron oxidation (dichloromethane, U = IV, platinum electrode, several days) to give bismuth bis(phthalocyanine).167... 

The reduction can also be performed electrochemically. For example, bis(triphenylphos-phane)iminium [trichlorozirconium(IV) phthalocyanine] can be reduced (dichloromethane, reflux, platinum electrode, 2 V, cathodic reduction) to a zirconium(III) species.222... 

The second important group of configuralionally stable bis-protected a-amino aldehydes are the V-dibenzvl derivatives 5, easily prepared from amino acids in a three-step procedure65. These aldehydes react with various nucleophiles to normally provide the nonchelation-con-trolled adducts in high diastereoselectivity. This anti selectivity is observed when diethyl ether or telrahydrofuran is used as reaction solvent. Certain Lewis acidic nucleophiles or additives, such as tin(IV) chloride, in dichloromethane as solvent force chelation and therefore provide the. syn-adducts, once again with a high diastereoselectivity. 

If the water content of the diazotization system is too high, the halogen atom in halogen-substituted mono- and dinitroanilines may be replaced by a hydroxy group in a bimolecular aromatic substitution. Analogous behaviour was observed in the diazotization of pentafluoroaniline, where the 4-fluoro substituent became hydrolysed (Brooke et al., 1965). As already mentioned in Section 2.1, this side reaction does not take place if the diazotization is conducted in a dichloromethane-aqueous sulfuric acid two-phase system in the presence of tetrakis[3,5-bis(trifluoromethyl)-phenyl]borate (Iwamoto et al., 1983a, 1984). 

As in the preceding subsection, l,2-bis(benzenesulfonylimino)-4,5-dimethyl-benzene (598) and 2-phenylthiazolo[3,2-fl]quinolinium-l-olate (599) in dichloromethane at 20°C during 15 min afforded l,4-bis(benzenesulfonyl)-6,7-dimethyl-3-phenyl-3-(quinolin-2-ylthio)-3,4-dihydro-2(l//)-quinoxalinone (600) in almost quantitative yield. " ... 

III) and m-(triethylphosphoniodithio-formate-S,S )bis[tris (pentafluorophenyl) gold(III)] dichloromethane (1/1). 

Crespo, O., Gimeno, M.C., Laguna, A. and Villacampa, M.D. (1998) p-[7,8-Bis (diphenylphosphino)-7,8-dicarba-nido-undecaborato-lkP, 2kP ] (pentafluorophenyl-lkC) (triphenylphosphine-2kP)digold(l) dichloromethane solvate. Acta Crystallographica, Section C Crystal Structure Communications, C54(2), 203-205. 

Cespedes, C. and Vega, J.C. (1994) Reactions Of Dichloromethane With Thioanions. 1. Preparation Of Bis(N,N-Dialkylfhiocarbamoylthio) Methanes. Phosphorus, Sulfur Silicon Related Elements, 90(1—4), 155—158. 

In 2001, a new chiral bis(benzothiazines) ligand was reported by Harmata et al. and successfully applied to the test reaction (Scheme 1.58). The authors studied, in particular, different reaction conditions to perform this reaction and proved that good yields and enantioselectivities were obtained in relatively nonpolar solvents, whereas the reaction remained racemic in dichloromethane... 

Figure 4.2. TRIR difference spectra averaged over the timescales indicated following 266 nm photolysis of (a) diphenyl diazomethane (3.6mM) and (b) bis-(4-methoxyphenyl)-diazomethane (1.1 mM) in C02-saturated dichloromethane. Reprinted with permission from B. M. Showalter and J. R Toscano, J. Phys. Org. Chem. 2004,14,743. Copyright 2004, John Wiley Sons Limited.

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