Methyl 1-methylpropyl carbonate

In 1999, Ube Industries, Ltd. discovered carbonates containing branched alkyl groups, such as methyl 1-methylpropyl carbonate (155) and methyl sec- >vXy carbonate (156) [149]. 

Based on the concepts discussed in Section 2.3 above, it is clear that to optimize the electrolyte solution for chemical and electrochemical stability, and for conductivity, a mixed solvent approach is required. Eor chemical and electrochemical stability, clearly solvents containing EC, EMC, DMC and, to a lesser extent, DEC are required other useful asymmetric carbonate-based solvents have also been studied, e.g. ethylpropyl and isopropylmethyl carbonates [45], methylpropyl carbonate [83] and 2-methoxyethyl (methyl) carbonate [84], but the key solvents for electrochemical stability are EC, EMC and DMC. The superiority of a 1 1 1 (by volume) mixture of EC EMC DMC with 1 nrtol dm" LiPFe was reported in [85], and 1 1 1 (by volume) of EC EMC DEC with 1 mol-dm LiPFe was reported in [86]. Figure 10 summarizes the conductivities of various electrol 4es in 1 1 1 mixtures of EC EMC DMC and EC DEC DMC. At 0°C, the conductivities of 1 mol-dm LiPFe solutions are ITO S-cm" wltile those for LiMe and LiBETT are aU 0.5TO S-cm The low temperature cycling behavior of Li-ion cells in LiPFg solutions is superior in the EC EMC DMC electrolyte (e.g., compare Figures 11 and 12). 

Tirey et al. (1993) evaluated the degradation of phorate at three different temperatures. When oxidized at temperatures of 200, 250, and 275 °C, the following reaction products were identified by GC/MS ethanol, ethanethiol, methyl mercaptan, 1,2,4-trithiolane, 1,1-thiobisethane, 1,1 -(methylenebis(thio))bisethane, 1,3,5-trithiane, 0,0-diethyl-5-pentenyl phosphorodithioic acid, ethylthioacetic acid, diethyl disulfide, 2,2 -dithiobisethanol, ethyl-(1-methylpropyl) disulfide, sulfur dioxide, carbon monoxide, carbon dioxide, sulfuric acid, and phosphine. 

Scheme 16 The U-4CR with 2-Isocyano-2-methylpropyl Methyl Carbonate ...

An aldehyde (8 mmol) and a primary amine (8 mmol) were stirred in MeOH (16 mL) at 25 °C for 2h. 2-Isocyano-2-methylpropyl methyl carbonate (53 8 mmol) and a carboxylic acid (8 mmol) were then added and the mixture was stirred for 24 h. The solvent was removed, and the product 54 was isolated by flash chromatography (silica gel, hexane/EtOAc 3 1) as a mixture of rotamers. 

When 2-hydroxy-3,5-diphenylpyrazine 1-oxide was heated under reflux with an excess of acetic anhydride, a crystalline triacetoxy compound was obtained which was thought to have an open chain structure [AcO-CH=CPh-N=CPh-C(OAc)=N-OAc], but when the 2-hydroxypyrazine-l-oxide was boiled with a mixture of acetic anhydride and acetic acid, 2,6-diacetoxy-3,5-diphenylpyrazine was obtained (873) which was hydrolyzed by potassium hydrogen carbonate in methanol to 2,6-dihydroxy-3,5-diphenylpyrazine (873). 2-Hydroxy-5-methyl-3-phenylpyrazine 1-oxide behaved differently and when refluxed with acetic anhydride gave 5-acetoxymethyl-2-hydroxy-3-phenylpyrazine (100) and 2-hydroxy-3-methyl-5-phenylpyrazine 1-oxide similarly gave 3-acetoxymethyl-2-hydroxy-5-phenylpyrazine (873). When 2- l-hydroxy-2 -methylpropyl)-5-isobutylpyrazine 1-oxide was heated with a mixture of acetic anhydride and sodium acetate on a water bath 2-(l -acetoxy-2 -methylpropyl)-5-isobutylpyrazine 1 oxide was obtained (760a). 

The resorcinols used as starting materials in the present process are either resorcinol itself (III, R=H) or a 5-alkylresorcinol (III, R=alkyl). The alkyl group may have up to twelve carbon atoms and it may be either branched or straight-chained. Examples of such alkyl groups are methyl, ethyl, propyl, sec-butyl, pentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, l-ethyl-2-methylpropyl, isohexyl, heptyl, 1-methylhexyl, 1,2-dimethylhexyl, 1,2-dimethylheptyl, 1-methyloctyl, and 1-methylnonyl. 

Methyl phthalate, see Dimethyl phthalate 2-(l-Methylpropyl)-4,6-dinitrophenol, see Dinoseb 6-Methyl-2,3-quinoxaline dithiocarbonate, see Quinomethionate 6-Methyl-2,3-quinoxalinedithiol cyclic carbonate, see Quinomethionate 6-Methyl-2,3-quinoxalinedithiol cyclic dithiocaibonate, see Quinomethionate... 

When a methyl group is attached to the Cl carbon of the branch chain and four or more carbons are in the substituent, the common term used is secondary or sec. The 1-methylpropyl fragment is therefore sec-butyl and the 1-methylbutyl fragment is sec-pentyl or sec-amyl. A special fragment, the 2,2-dimethylpropyl fragment, is known as neopentyl (see Table 4.2). It is important to emphasize that these common names should not be used when a molecule is given an lUPAC name. From time to time, however, common names will be mentioned in this text. 

A specific example of an aldehyde is 13, nonanal. Note the use of nonan and al, where the former is derived from the saturated nonane skeleton. The e is dropped and replaced with al. Substituents attached to the aldehyde chain are named in the usual manner, with the carbonyl carbon always numbered 1. Aldehyde 14 has a 10-carbon alkane chain, so it is a decanal. Using the carbonyl carbon as Cl, there is a 1-methylpropyl group at C3 and a methyl group at C5. Therefore, the name is 5-methyl-3-(l-methylpropyl)decanal (the decanal chain is marked in blue in the illustration). 

Problem 3.4. For the dodecane isomer shown in V above [2-methyl-3-(l-methylpropyl)-heptane], decide which carbon atoms have four different ligands attached. Represent the asymmetrically substituted carbon atoms appropriately and determine if they can be superimposed upon their realized mirror images. 

Fig. 1. Molar optical rotation ([0] vs polymerized monomer optical purity of isotactic vinyl polymers having the asymmetric carbon atom in the oc and 3 position to the main chain. -O poly-(5)-4-methyl-l-hexene - t- poly-(5)-3,7-dimethyl-l-octene poly- (5)-l-methylpropyl]-vinyl ether.

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