Studies on the Mucohalic Acids. I. The Structure of Mucoxychloric Acid¹

Regioisomeric α-hydroxy chlorohydrins from the reaction of mucochloric acid and guanosine

“…19 In the open-chain form, it is the aldehyde carbon that is susceptible to attack by a nucleophile and this course is consistent with labeling experiments performed on analogous reactions. 8,12 Interestingly, the chlorine in position 3 of MCA (1) is susceptible to net displacement by hydroxide ion to yield mucoxychloric acid (7), 20 another potential electrophile. However, the aldehyde group in the open-chain form of 1 is a powerful electrophile and as such can be expected to be less than discriminating.…”

Recent Progress in the Chemistry of Mucohalic Acids: Versatile Building Blocks in Organic Synthesis

“…It was found that under these modified conditions (10 mol% H 2 SO 4 in AcOH), the reaction completed in only 30 minutes and the product was isolated in 98% yield (Table 3). These conditions were also suitable for the reaction from mucobromic acid (2), and the desired product 78 was isolated in 92% yield. With these building blocks in hand, we explored further transformations.…”

“…Mucohalic acid 1 is the common generic name for mucochloric acid (1) [3,4-dichloro-5-hydroxyfuran-2(5H)-one] and mucobromic acid (2) [3,4-dibromo-5-hydroxyfuran-2(5H)-one] (Scheme 1). These substances are inexpensive, commercially available starting materials consisting of multiple functionalities: one double bond between C-2 and C-3 with Z-configuration, two halogen atoms attached to the sp 2 carbons, and two carbonyl groups possessing different reactivity at C-1 and C-4.…”

Intramolecular Reversible Addition Reactions to the C=O Group

“…The cyclization is accompanied by 1,4-dehydration to the lactone (17) [88-90]: o (17) o Z-3-Acylacrylic Acids (le). Z-3-Formylacrylic acid [2,35,91,92], its 2-methyl [93], 3-methyl [94], 2,3-halogeno [11,17,[95][96][97][98], and other 2,3substituted derivatives [99], and also Z-3-acetylacrylic acids [15,20,[100][101][102][103], exist in the solid state, as well as in solution, entirely in the ring form (18B) as does penicillic (Z-3-methacryl-3-methoxyacrylic) acid [104,105].…”