Ethyl 1-benzyl-5-{[(isopropyl-amino)(3-nitro-phen-oxy)methyl-idene]amino}-1H-1,2,3-triazole-4-carboxyl-ate.

In the title compound, C(22)H(24)N(6)O(5), the triazole ring is essentially planar with a maximum deviation of 0.005 (2) Å and forms dihedral angles of 79.78 (11) and 86.

3-Benzyl-6-butyl-5-propyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

In the title compound, C(18)H(23)N(5)O(2), the triazolopyrimidine ring system is essentially planar, with a maximum displacement of 0.032 (2) Å, and forms a dihedral angle of 87.59 (15)° with the phenyl ring.

6-Butyl-5-(4-methyl-phen-oxy)-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

In the title compound, C(21)H(21)N(5)O(2), the triazolopyrimidine ring system is essentially planar [maximum displacement = 0.021 (4) Å] and forms dihedral angles of 41.17 (9) and 67.

6-Isopropyl-5-meth-oxy-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

In the title compound, C(14)H(15)N(5)O(2), the whole mol-ecule apart from the terminal C atoms of the isopropyl group is located on a crystallographic mirror plane. An intra-molecular C-H⋯N hydrogen-bonding inter-action may stabilize the mol-ecular conformation. The crystal packing features weak slipped π-π inter-actions between the pyrimidine and the phenyl rings of symmetry-related mol-ecules [centroid-centroid distance = 3.

Ethyl (2,5-dioxo-1-phenyl-2,3-dihydro-1H,5H-1-benzofuro[3,2-d]imidazo[1,2-a]pyrimidin-3-yl)acetate.

In the title compound, C(22)H(17)N(3)O(5), synthesized via the aza-Wittig reaction of ethyl 3-(phenyl-imino-methyl-ene-amino)-benzofuran-2-carboxyl-ate, benzene isocyanate and diethyl 2-amino-succinate, the imidazo[1,2-a]benzo[4,5]furo[2,3-d]pyrim-idine ring system is essentially planar (r.m.s.

3-Isopropyl-2-p-tol-yloxy-5,6,7,8-tetra-hydro-1-benzothieno[2,3-d]pyrimidin-4(3H)-one.

In the title compound, C(20)H(22)N(2)O(2)S, the central thieno-pyrimidine ring system is essentially planar, with a maximum displacement of 0.023 (2) Å. The attached cyclo-hexene ring is disordered over two possible conformations, with an occupancy ratio of 0.

6-Butyl-5-(4-methoxy-phen-oxy)-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

The asymmetric unit of the title compound, C(21)H(21)N(5)O(3), consists of two geometrically similar mol-ecules. The fused rings of the triazolo[4,5-d]pyrimidine system are nearly coplanar, making dihedral angels of 1.48 (18) and 1.

3-Benzyl-6-isopropyl-5-phen-oxy-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

In the title compound, C(20)H(19)N(5)O(2), all atoms of the 1,2,3-triazolo[4,5-d]pyrimidine ring system are essentially coplanar [maximum deviation = 0.015 (2) Å], indicating the existence of a conjugate system in which each carbon and nitrogen atom is sp(2) hybridized and ten π electrons (three from carbon atoms and seven from nitrogen atoms) constitute an aromatic heterocycle. The ring system forms dihedral angles of 68.

6-Isopropyl-3-phenyl-5-(p-tol-yloxy)-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one: whole-mol-ecule disorder.

The title compound, C(20)H(19)N(5)O(2), exhibits whole-mol-ecule disorder the refined ratios of the two components being 0.57 (2):0.43 (2).

5-(4-Chloro-phen-oxy)-6-isopropyl-3-phenyl-3H-1,2,3-triazolo[4,5-d]pyrimidin-7(6H)-one.

In the title compound, C(19)H(16)ClN(5)O(2), the triazolopyrimidine ring system is essentially planar, with a maximum displacement of 0.021 (4) Å, and forms dihedral angles of 1.09 (9) and 87.