Bis(2,5-dimethoxy-4-methylphenyl)methane, C(19)H(24)O(4), (IIa), was obtained and characterized as a minor product from the reaction of toluhydroquinone dimethyl ether (1,4-dimethoxy-2-methylbenzene) with N-(hydroxymethyl)trifluoroacetamide. Similarly, bis(2,5-dimethoxy-3,4,6-trimethylphenyl)methane, C(23)H(32)O(4), (IIb), was prepared from the corresponding reaction of trimethylhydroquinone dimethyl ether (2,5-dimethoxy-1,3,4-trimethylbenzene). The molecules of (IIa) and (IIb) each lie on a twofold axis passing through the methylene group. The dihedral angle between the planar phenyl rings is 73.4 (1) degrees in (IIa) and 77.9 (1) degrees in (IIb). The external bond angles around the bridging methylene group are 116.6 (2) and 117.3 (2) degrees for (IIa) and (IIb), respectively. In (IIa), the methoxy substituents lie in the plane of the ring and are conjugated with the aromatic system, whereas in (IIb), they are almost perpendicular to the phenyl ring and are positioned on opposite sides.

We have developed large-scale efficient procedures for the conversion of commercially available [(13) C]- or [(2) H3 ,(13) C]methanol and (13) CO2 or (13) C-labeled bromoacetic acid to 2-(phenylthio)[1,2-(13) C2 ]-, [1-(13) C]-, and [2-(13) C]acetic acid. The resulting derivatives are versatile, chemically stable, and nonvolatile two-carbon labeling precursors. We have used the (13) C-isotopomers of 2-(phenylthio)acetic acid in the synthesis of (13) C-labeled acrylic acid, methacrylic acid, and trans-crotonic acid.

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The 1,3-dithiane is a protected formaldehyde anion equivalent that could serve as a useful labeled synthon. We report a facile synthesis of 1,3-[2-(13)C]- and 1,3-[2-(13)C, 2-(2)H2]dithiane in two steps from [(13)C]- or [(13) C, (2)H3 ]methyl phenyl sulfoxide. We have previously reported the high yield synthesis of [(13)C]methyl phenyl sulfide from [(13)C]MEOH and the oxidation of [(13)C]methyl phenyl sulfide to [(13)C]methyl phenyl sulfoxide. Here, we describe the facile exchange of deuterium from (2) H2 O into [(13)C]methyl phenyl sulfoxide to yield [(13)C, (2)H3]methyl phenyl sulfoxide. Thus, from [(13)C]MEOH and (2)H2O, all possible C2 stable isotopomers of 1,3-dithiane are available. Our synthetic route is also amenable to preparation of radiolabeled 1,3-dithianes.