995. Dehydroacetic acid and its derivatives

Marine natural products

“…292 An endophytic strain of Eurotium rubrum, (semi-mangrove Hibiscus tiliaceus, Hainan Is., China) produced a diketopiperazine alkaloid 12-demethyl-12-oxo-eurotechinulin B 351 and an anthraquinone derivative 9-dehydroxyeurotinone 352, 296 in addition to the known fungal metabolites variecolorin G 297 and alkaloid E-7. 297,298 The alkaloids N-2-methylpropyl-2-methylbutenamide 353, fusarine 354 and fusamine 355 were discovered from endophytic Fusarium incarnatum (mangrove fruit Aegiceras corniculatum, Xiamen, Fujian, China) 299 along with the known synthetic compounds, 2-acetyl-1,2,3,4-tetrahydro-b-carboline 300 and 3-(1-aminoethylidene)-6-methyl-2H-pyran-2,4(3H)-dione, 301 reported as rst time MNPs. Fusarine was concurrently isolated from the Chinese plant Alhagi sparsifolia.…”

Reactions of dehydroacetic acid and related pyrones with secondary amines

“…An additional crystallization from benzene-cyclohexane mixture furnished an analytical sample, mp 110-112°. Enedione 3 gave an intense green color with ethanolic ferric chloride: ir (KBr) 3.38 (CH3 and CH¡¡), 3.54 (NCH2), 4 (weak, broad, chelated OH), 6.1 (strong, C=C), 6.35 and 6.45 (very strong, chelated conjugated C=0 and C=C), 7.27 (CCH3), 7.52, 8.75, 9.70 and 12.37 µ (RR'C=CHR"). The solution ir (CHClj) shows an additional band at 5.85 µ (C==0); nmr (benzene-d6) 8 5.32 (s, 0.8, -CH=C(OH)-), and 17.62 (broad s, 7 _ CO 0.8, intramolecularly chelated OH).…”

The crystal structure of nickel(II)-dehydroacetic acid monoimide complex

“…Iguchi, Hisatsune, Himeno & Muraoka, 1959), and the structures of the products were studied in detail by infrared 0"4556 0" 1128 0"0587 2"31 67 71 89 0(3) 0"1666 0"3192 0"3581 2"84 80 76 88 0(4) 0"5538 -0"0521 -0"0293 2-41 70 75 87 0(5) 0"2571 0" 3731 0" 1708 3"93 85 95 102 0(6) 0"4620 --0"1067 0"1461 2"94 73 76 95 N(1) 0"3850 0"2135 0"0530 2"19 81 82 98 N(2) 0"3427 0"0565 0"3473 2"35 81 83 98 C(1) 0"2439 0'2096 0"3270 2"23 91 101 122 C(2) 0"4832 0"0583 0"0458 2"24 99 98 123 C(3) 0"1706 0"2116 0"4573 2"33 102 104 125 C(4) 0"5548 0"0551 -0"0829 2"38 100 104 127 C(5) 0"1354 0"2642 0"4649 2"38 103 98 120 C(6) 0"5891 0"0011 -0"1207 2"09 93 97 114 C (7) 0"2375 0"3218 0'2473 2"72 99 101 139 C(8) 0"4854 -0"0547 0"0971 2"44 101 103 121 C(9) 0"2770 0"2640 0"2110 2"10 89 92 120 C(10) 0"4476 0"0029 0"1563 1"95 87 92 118 C(ll) 0"0592 0"2736 0"5875 2"95 113 114 142 C(12) 0"6622 -0"0084 -0"2467 2"59 102 101 138 C(13) 0"3485 0"2652 0"0738 2"01 89 94 115 C (14) 0"3786 0"0035 0 0"00216 0"00146 0.07196 0"00009 0"00288 e.s.d. 's 0"00004 0.00003 0"00142 0"00006 0"00043 Final shifts 0.00000 0.00000 0.00052 0.00000 0-00004 a(B) 0.11 0"13 0.14 0"13 0.17 0"14 0.14 0"14 0"16 0"17 0"17 0"17 0"16 0"15 0"18 0"18 0"18 0"15 0"20 0"17 0"16 0"15 0"17 0"17 fl23 --0"00035 0"00037 --0"00002 absorption and proton magnetic resonance measurements (Edwards, Page & Pianka, 1964). The resultant dehydroacetic acid monoimide (hereafter referred to as DHA imide), or 3-(1-iminoethyl)-4-hydroxy-6methyl-2-pyrone, forms metal complexes with some metal ions such as copper(II) ion, which were expected to be chelate compounds (Iguchi & Goto, 1959).…”