5-Butyl-6-methyl-2-thioxo-2,3-dihydropyrimidin-4(1 H )-one

The molecules of the title compounds, C7H8N2OS, (1), C14H13FN2OS, (2), and C17H17FN2O3S, (3), crystallize in the space groups C2/m, C2/c and Ia, respectively. Compounds (1) and (2), an S-alkylated derivative of (1), consist of only one symmetry-independent molecule, while (3), an O-alkylated derivative of (2), contains two independent molecules in the asymmetric unit. The molecules of (1) sit on crystallographic mirror planes. In the supramolecular structure of (1), a combination of N-H···O and N-H···S hydrogen bonds creates a molecular strap with C(6) and R2(2)(8) motifs, which is further stabilized by an S···S contact. In the packing of (2), a one-dimensional molecular column is made up of two kinds of dimers. One dimer, with an R2(2)(18) motif, is formed by a pair of C-H···O soft hydrogen bonds and the other, with an R2(2)(8) motif, is produced via a pair of N-H···O hard hydrogen bonds. In the packing of (3), molecules A and B form two different types of one-dimensional chain by intermolecular C-H···N hydrogen bonds, and by C···N and O···S contacts, respectively. Two such kinds of chain are connected alternately via interchain C-H···O hydrogen bonds, giving a two-dimensional sheet. Finally, a three-dimensional supramolecular structure is formed through weak intersheet C-H···F hydrogen bonds. The study of the molecular and supramolecular structures of thiouracil derivatives is significant in the development of lipoprotein-associated phospholipase A2 inhibitors.

Section: Resultsmentioning

confidence: 77%

Supramolecular structures in three thiouracil derivatives: 5,6-trimethylene-2-sulfanylidene-1,2-dihydropyrimidin-4(3H)-one, 2-(4-fluorobenzylsulfanyl)-5,6-trimethylenepyrimidin-4(3H)-one and methyl 2-{[2-(4-fluorobenzylsulfanyl)-5,6-trimethylenepyrimidin-4-yl]oxy}acetate

Zhou

et al. 2014

“…Nine of these structures show R 2 2 (8) motifs with two N-HÁ Á ÁO hydrogen bonds [refcodes FAJWES (Brewer et al, 1987), FICBEY , HEPMIY (Pastor et al, 1994), MUYTIK (Ivanova & Spiteller, 2010), HAFLAC (Antoniadis et al, 2003), LACJIJ (Tashkhodzhaev et al, 2002), EBAQOP (Balas et al, 2011), and EBAQOP01 and DAYGUH (Kubicki et al, 2012)] and 11 structures contain R 2 2 (8) motifs characterized by two N-HÁ Á ÁS hydrogen bonds [FALWOF (Orzeszko et al, 2004), FUWBOP (Medda et al, 2009), LOFDAL (Fonar et al, 1999), MUGMIK (Matković-Č alogović et al, 2002), PABNAJ, PABNIR (Chierotti et al, 2010), QAYCID (Van Hecke et al, 2005), QEHSEB (Tiekink, 2001), ZZZGEO01 (Delage, H'Naifi, Goursolle & Carpy, 1986), and CALFUS and CALGAZ (Tutughamiarso & Egert, 2011)]. In nine structures, two different R 2 2 (8) motifs with either two N-HÁ Á ÁO or two N-HÁ Á ÁS hydrogen bonds can be observed [CASPUI (Hu et al, 2005), GEMCAC (Read et al, 1988), PABPAL (Chierotti et al, 2010), RAPNAY (Long et al, 2005), TURCIL01 (Tiekink, 1989), TURCIL02 (Munshi & Guru Row, 2006), UXIXUV (Ferreira et al, 2011), UXIXUV01 (Tutughamiarso & Egert, 2011) and LANZIL (Al-Deeb et al, 2012)].…”

Section: Figurementioning

confidence: 99%

Five pseudopolymorphs of 6-amino-2-thiouracil: absence of N—H...S hydrogen bonds

Hützler

Bolte

2012

In order to study the preferred hydrogen-bonding pattern of 6-amino-2-thiouracil, C(4)H(5)N(3)OS, (I), crystallization experiments yielded five different pseudopolymorphs of (I), namely the dimethylformamide disolvate, C(4)H(5)N(3)OS·2C(3)H(7)NO, (Ia), the dimethylacetamide monosolvate, C(4)H(5)N(3)OS·C(4)H(9)NO, (Ib), the dimethylacetamide sesquisolvate, C(4)H(5)N(3)OS·1.5C(4)H(9)NO, (Ic), and two different 1-methylpyrrolidin-2-one sesquisolvates, C(4)H(5)N(3)OS·1.5C(5)H(9)NO, (Id) and (Ie). All structures contain R(2)(1)(6) N-H...O hydrogen-bond motifs. In the latter four structures, additional R(2)(2)(8) N-H...O hydrogen-bond motifs are present stabilizing homodimers of (I). No type of hydrogen bond other than N-H...O is observed. According to a search of the Cambridge Structural Database, most 2-thiouracil derivatives form homodimers stabilized by an R(2)(2)(8) hydrogen-bonding pattern, with (i) only N-H...O, (ii) only N-H...S or (iii) alternating pairs of N-H...O and N-H...S hydrogen bonds.

“…19 entries showed R 2 2 (8) motifs characterized by two N-HÁ Á ÁO hydrogen bonds; the S atoms take part as acceptors only in five of them [refcodes LACJIJ (Tashkhodzhaev et al, 2002), XUHJIY (Pawlowski et al, 2009), XEXWAZ, XEXWED and XEXWIH (Balalaie et al, 2006)], whereby chains stabilized by N-HÁ Á ÁS hydrogen bonds are observed only in XUHJIY. Nine structures contain two different R 2 2 (8) patterns with either two N-HÁ Á ÁO or two N-HÁ Á ÁS hydrogen bonds [refcodes CASPUI (Hu et al, 2005), CUKBOA (Hori et al, 2009), GEMCAC (Read et al, 1988), PABPAL (Chierotti et al, 2010), RAPNAY (Long et al, 2005), TURCIL01 (Tiekink, 1989), TURCIL02 (Munshi & Guru Row, 2006), WIVJAM (Coxall et al, 2000) and ZEWDOU (Ferrari et al, 1995)]. Furthermore, six entries showed R 2 2 (8) interactions consisting of two N-HÁ Á ÁS hydrogen bonds [refcodes FALWOF (Orzeszko et al, 2004), JESWEK (Xue et al, 2006), MTURAC (Hawkinson, 1975), PABNIR (Chierotti et al, 2010), VOKBUT (Luo et al, 2008) and ZUWMUZ (Branch et al, 1996)].…”

Section: Figurementioning

confidence: 99%

Cocrystals of 6-propyl-2-thiouracil: N—H...OversusN—H...S hydrogen bonds

Tutughamiarso

Egert

2011

In order to investigate the relative stability of N—H...O and N—H...S hydrogen bonds, we cocrystallized the antithyroid drug 6‐propyl‐2‐thiouracil with two complementary heterocycles. In the cocrystal pyrimidin‐2‐amine–6‐propyl‐2‐thiouracil (1/2), C4H5N3·2C7H10N2OS, (I), the `base pair' is connected by one N—H...S and one N—H...N hydrogen bond. Homodimers of 6‐propyl‐2‐thiouracil linked by two N—H...S hydrogen bonds are observed in the cocrystal N‐(6‐acetamidopyridin‐2‐yl)acetamide–6‐propyl‐2‐thiouracil (1/2), C9H11N3O2·2C7H10N2OS, (II). The crystal structure of 6‐propyl‐2‐thiouracil itself, C7H10N2OS, (III), is stabilized by pairwise N—H...O and N—H...S hydrogen bonds. In all three structures, N—H...S hydrogen bonds occur only within R22(8) patterns, whereas N—H...O hydrogen bonds tend to connect the homo‐ and heterodimers into extended networks. In agreement with related structures, the hydrogen‐bonding capability of C=O and C=S groups seems to be comparable.