(3,5-Dimethyl-1H-pyrazol-1-yl){3-[(3,5-dimethyl-1H-pyrazol-1-yl)carbon-yl]-5-methyl-indolizin-1-yl}methanone.

There are two independent mol-ecules in the asymmetric unit of the title compound, C21H21N5O2. In each mol-ecule, the indolizine ring system is essentially planar, with r.m.s. deviations of 0.030 and 0.028 Å. The dihedral angles between the indolizine ring system and the pyrazole rings are 54.7 (3) and 8.6 (3)° in one mol-ecule and 54.4 (3) and 6.6 (3)° in the other. In the crystal, weak C-H⋯O and C-H⋯N hydrogen bonds link mol-ecules, forming a two-dimensional network parallel to (100).

1-[(3,5-Dimethyl-1H-pyrazol-1-yl)carbon-yl]-5-methyl-indolizine-3-carbo-nitrile.

In the title mol-ecule, C16H14N4O, the indolizine ring system is essentially planar, with a maximum deviation of 0.013 (3) Å, and forms a dihedral angle of 7.52 (12)° with the pyrazole ring. In the crystal, weak C-H⋯O hydrogen bonds and π-π stacking inter-actions, with a centroid-centroid distance of 3.6378 (16) Å, link mol-ecules along [001].

Ethyl 3-benzoyl-indolizine-1-carboxyl-ate.

The title compound, C(18)H(15)NO(3), consists of an indolizine ring system and an aromatic ring. The two ring systems are not coplanar, the dihedral angle between the two being 54.26 (7)°. In the crystal, inversion dimers are formed by weak C-H⋯O interactions. These dimeric groups are further extended to form a regular two-dimensional structure by additional weak C-H⋯O inter-actions.

Iron-catalyzed domino decarboxylation-oxidation of α,ß-unsaturated carboxylic acids enabled aldehyde C-H methylation.

A practical and general iron-catalyzed domino decarboxylation-oxidation of α,ß-unsaturated carboxylic acids enabling aldehyde C-H methylation for the synthesis of methyl ketones has been developed. This mild, operationally simple method uses ambient air as the sole oxidant and tolerates sensitive functional groups for the late-stage functionalization of complex natural-product-derived and polyfunctionalized molecules.

(9H-Carbazol-9-ylmeth-yl)diethyl-amine.

The asymmetric unit of the title compound, C(17)H(20)N(2), contains two mol-ecules, whose bond lengths and angles differ only slightly. In the crystal, neighbouring mol-ecules form pillar structures via edge-to-face π-π stacking inter-actions [edge-to-face distances = 3.538 (3) and 3.496 (3)Å].

Diethyl indolizine-1,3-dicarboxyl-ate.

The title compound, C(14)H(15)NO(4), was prepared by a 1,3-dipolar cyclo-addition from N-(eth-oxy-carbonyl-methy)pyridinium bromide and ethyl acrylate. The -CO(2) side chains form dihedral angles of 0.2 (3) and 2.4 (3)° with respect to the ring system. In the crystal, two neighbouring mol-ecules form a dimer through weak C-H⋯O interactions. The dimers form a three-dimensional structure via further weak C-H⋯O inter-actions.

(Pyridine-2,6-diyldimethyl-ene)bis-(diphenyl-methanol).

In the title compound, C(33)H(29)NO(2), the central pyridyl ring makes dihedral angles of 42.71 (16), 44.78 (16), 85.47 (12) and 76.74 (12)° with the four phenyl rings. There are two intra-molecular O-H⋯N hydrogen bonds. In the crystal structure, mol-ecules are linked into a chain running along the b axis by a weak C-H⋯π inter-action.

Dimethyl 9-benzyl-3-cyano-9H-pyrrolo[1,2-a]benzimidazole-1,2-dicarboxyl-ate.

The title compound, C(22)H(17)N(3)O(4), was prepared through 1,3-dipolar cyclo-addition: the dihedral angle between the benzimidazole and benzene rings is 80.93 (6)°. The crystal structure is stabilized by weak π-π inter-actions between the planar pyrrolobenzimidazole rings (r.m.s. deviation = 0.0293 Å) of neighbouring mol-ecules, forming chains along the c axis. The perpendicular distance is 3.47 (2) Šand the centroid-centroid distances are in the range of 3.590 (3)-3.944 (3) Å.

Iron-catalyzed oxidative C-C(vinyl) σ-bond cleavage of allylarenes to aryl aldehydes at room temperature with ambient air.

A general and selective iron-catalyzed allylic C-C(vinyl) σ-bond cleavage of allylarenes without the assistance of heteroatoms to give aryl aldehydes is reported. The unstrained carbon-carbon single bond cleavage reaction uses ambient air as the sole oxidant, proceeds efficiently at room temperature, and allows for exceptional functional-group tolerance, which addresses the long-standing challenges of current C-C bond cleavage/functionalization. Notably, the method enables rapid late-stage oxidation of complex bioactive molecules and can be used to expedite syntheses of natural products (vanillin and glucovanillin) from readily available chemical feedstocks.

Bio-inspired iron-catalyzed oxidation of alkylarenes enables late-stage oxidation of complex methylarenes to arylaldehydes.

It is a long-standing challenge to achieve efficient and highly selective aerobic oxidation of methylarenes to benzaldehydes, owing to overoxidation problem stemming from the oxidizability of benzaldehyde far higher than the toluene under usual aerobic conditions. Herein we report a bio-inspired iron-catalyzed polymethylhydrosiloxane-promoted aerobic oxidation of methylarenes to benzaldehydes with high yields and selectivities. Notably, this method can tolerate oxidation-labile and reactive boronic acid group, which is normally required to be transformed immediately after its introduction, and represents a significant advance in the area of the chemistry of organoboronic acids, including the ability to incorporate both aldehyde and ketone functionalities into unprotected arylboronic acids, a class that can be difficult to access by current means. The robustness of this protocol is demonstrated on the late-stage oxidation of complex bioactive molecules, including dehydroabietic acid, Gemfibrozil, Tocopherol nicotinate, a complex polyol structure, and structurally complex arylboronic acids.

2-(6-Methyl-2-pyrid-yl)-1,1-diphenyl-ethanol.

The title compound, C(20)H(19)NO, was prepared from 2,6-lutidine and benzophenone. There are two symmetry-independent mol-ecules in the asymmetric unit. Each mol-ecule is involved in one intra-molecular O-H⋯N hydrogen bond. In the crystal structure, helical chains are formed along the b axis by weak π-π inter-actions between neighbouring mol-ecules [centroid-centroid distances between the pyridyl rings of the two independent mol-ecules = 4.041 (3) and 4.051 (3) Å].

A novel pyrazole-containing indolizine derivative suppresses NF-κB activation and protects against TNBS-induced colitis via a PPAR-γ-dependent pathway.

The nuclear factor-κB (NF-κB)-mediated activation of macrophages plays a key role in mucosal immune responses in Crohn's disease (CD). Moreover, increasing evidence shows that the activation of peroxisome proliferator-activated receptor-γ (PPAR-γ) exerts satisfactory anti-inflammatory effects in experimental colitis models, mostly by suppressing NF-κB-mediated macrophage activation. Therefore, exploring therapeutic strategies to activate PPAR-γ and inhibit the NF-κB pathway in colonic macrophages holds great promise for the treatment of CD. In this study, five novel pyrazole-containing indolizine derivatives (B1, B2, B3, B4 and B5) were successfully synthesized and characterized, and their anti-inflammatory activities for CD treatment were also investigated. Among the five compounds, compound B4 effectively decreased the NF-κB-mediated production of the pro-inflammatory cytokine TNF-α in LPS-stimulated peritoneal macrophages. Moreover, compound B4 significantly ameliorated 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced mouse colitis symptoms, including body weight loss, colonic pathological damage and inflammatory cell infiltration. The results of western blotting and luciferase reporter assays indicated that compound B4 activated PPAR-γ and subsequently suppressed NF-κB activation. Conversely, the addition of the PPAR-γ antagonist GW9662 abrogated the anti-inflammatory effects of compound B4 both in vitro and in vivo. In summary, compound B4 activated the PPAR-γ pathway to inhibit downstream NF-κB signaling, which alleviated experimental colitis. Thus, this compound may serve as a potential therapeutic agent for patients with CD.