Stereoselective Dehydroxyboration of Allylic Alcohols to Access (E)-Allylboronates by a Combination of C-OH Cleavage and Boron Transfer under Iron Catalysis.

Iron-catalyzed direct SN2' dehydroxyboration of allylic alcohols has been developed to access (E)-stereoselective allylboronates. Allylic alcohols with diverse structures and functional groups, especially derived from natural products, underwent smooth transformation. The six-membered ring transition state formed by allylic alcohols and iron-boron intermediate was indicated to be the key component involved in transfer of the boron group, activation of the C-OH bond, and control of the stereoselectivity.

Synthesis and activity evaluation of the cyclic dipeptides arylidene N-alkoxydiketopiperazines.

A series of arylidene N-alkoxydiketopiperazines was designed and stereoselectively synthesized via oxime-ether formation and intramolecular acylation. Possible cyclization and acid-catalyzed rearrangement-fragmentation mechanisms were discussed. The crystal structure of the novel diketopiperazine further confirmed the rearrangement mechanism. Most compounds exhibited antitumor activity. Several compounds were more potent against caspase-3. Specifically, compounds 6e, 6g, and 6f inhibited caspase-3 at IC50 values lying within the low micromolar range and demonstrated good selectivity. The binding modes of alkoxydiketopiperazines in the active center of caspase-3 were also discussed based on the molecular docking results.

Synthesis and biological evaluation of open-chain analogs of cyclic peptides as inhibitors of cellular Shp2 activity.

A series of open-chain analogs of cyclic peptides was designed and synthesized using sansalvamide A as a model compound. All compounds exhibited low antitumor activity. Furthermore, the evaluation of their inhibitory potency toward IMPDH, SHP2, ACHE, proteasome, MAGL, and cathepsin B showed that all of the compounds were potent against protein tyrosine phosphatase Shp2. Specifically, compounds 1a, 1d, 2b, and 2f were found to inhibit SHP2 with IC50 values in the low micromolar range and good selectivity. Based on the molecular docking results, the binding modes of the chain cyclic peptides in the active center of SHP2 were discussed.

3-(3,4-Dihydroxyphenyl)-1-methoxy-1-oxopropan-2-aminium chloride.

In the title compound, C(10)H(14)NO(4) (+)·Cl(-), the benzene ring makes a dihedral angle of 64.68 (4)° with the methyl-amino-propano-ate unit, which is bonded to the catechol ring via a methyl-ene C atom. A strong intra-molecular O-H⋯O hydrogen bond occurs. In the crystal, O-H⋯O, N-H⋯Cl and O-H⋯Cl hydrogen bonds and weak C-H⋯O inter-actions link the mol-ecules into a three-dimensional network.

(Anthracen-9-ylmeth-yl)benzyl-ammonium chloride.

In the title compound, C(22)H(20)N(+)·Cl(-), the anthracene system makes a dihedral angle of 72.65 (4)° with the benzene ring. The C-N-C-C torsion angles in the chain connecting the benzene ring and anthracene system are 52.24 (15) and -170.73 (11)°. The crystal structure is stabilized by inter-molecular N-H⋯Cl and C-H⋯Cl hydrogen bonds, which link the mol-ecules into tetra-mers about inversion centers.

Dimethyl 2-(2-quinolylmeth-yl)malonate.

In the title compound, C(15)H(15)NO(4), the quinoline ring system and one of the malonate side chains are essentially coplanar (r.m.s. deviation = 0.0297 Å). The two malonate C-C(=O)-O-CH(3) side chains are oriented at right angles [89.68 (8)°] with respect to each other. The crystal packing is stabilized by weak non-classical inter-molecular C-H⋯O hydrogen bonds, which link the mol-ecules into dimers about inversion centers.

Dimethyl 2-(2,4,6-trimethoxy-benz-yl)malonate.

In the title compound, C(15)H(20)O(7), the benzene ring makes dihedral angles of 69.17 (5) and 80.81 (4)° with the two side chains of malonate. The two malonate side chains comprising C/C/O/C atoms are oriented at right angles [86.26 (6)°] with respect to each other. In the crystal structure, the crystal packing is stabilized by weak non-classical inter-molecular C-H⋯O hydrogen bonds, which link the mol-ecules into an infinite network.

11-(p-Tolylsulfonyl)-8,14,24-trioxa-11,22,23-triazatetracyclo[19.2.1.0.0]tetracosa-1(23),2,4,6,15,17,19,21-octaene.

In the title compound, C(25)H(23)N(3)O(5)S, the central 1,3,4-oxadiazole ring makes dihedral angles of 35.05 (7), 23.68 (7) and 82.55 (8)°, with the three benzene rings. In the crystal structure, the packing is stabilized by weak non-classical inter-molecular C-H⋯O hydrogen bonds, which link the mol-ecules into an infinite network.

2,5-Bis[2-(2-methoxy-ethoxy)phen-yl]-1,3,4-oxadiazole.

In the title compound, C(20)H(22)N(2)O(5), the central 1,3,4-oxadiazole ring is essentially planar [r.m.s. deviation from the best plane of 0.0011 Å] and makes dihedral angles of 4.10 (3) and 13.32 (4)° with the two benzene rings. In the crystal structure, the packing is stabilized by weak non-classical inter-molecular C-H⋯N hydrogen bonds, which link the mol-ecules into an extended network.

(E)-N'-[2-(4-Chloro-3-nitro-phenyl-sulfon-yloxy)-3-methoxy-benzyl-idene]isonicotinohydrazide acetic acid tetra-solvate.

In the title compound, C(20)H(15)ClN(4)O(7)S·4CH(3)COOH, the central o-vanillin group makes dihedral angles of 9.50 (11) and 42.86 (7)°, respectively, with its attached pyridine and nitro-benzene rings. The crystal packing is stabilized by N-H⋯O, O-H⋯O and O-H⋯N hydrogen bonds and C-H⋯O inter-actions, leading to an infinite three-dimensional network. A short intramolecular C-H⋯O contact is also seen.

(E)-4-[(1,5-Dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl)imino-meth-yl]phenyl 4-bromo-benzene-sulfonate.

In the title compound, C(24)H(20)BrN(3)O(4)S, the central benzene ring makes dihedral angles of 17.13 (13), 39.83 (13) and 58.37 (13)°, respectively, with the pyrazolone ring, the bromo-benzene ring and the terminal phenyl ring. In the crystal structure, the packing is stabilized by a weak non-classical inter-molecular C-H⋯O hydrogen bond which links the mol-ecules into a chain propagating in [100].

(E)-1,5-Dimethyl-4-[3-(4-nitro-benz-yloxy)benzyl-ideneamino]-2-phenyl-1H-pyrazol-3(2H)-one.

In the title compound, C(25)H(22)N(4)O(4), the central benzene ring, makes dihedral angles of 74.35 (6), 17.01 (8) and 62.19 (7)°, respectively, with the nitro-benzyl ring, the pyrazolone ring and the terminal phenyl ring. Inter-molecular C-H⋯O hydrogen bonds help to consolidate the crystal packing.