Dehydro­abietic acid

The title compound [systematic name: (1R,4aS,10aR)-7-iso­prop­yl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa­hydro­phen­anthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent mol­ecules exist in the asymmetric unit. In each mol­ecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclo­hexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by inter­molecular O—H⋯O hydrogen bonds

7-Isopropyl-1,4a-dimethyl-1,2,3,4,4a,5,6,7,8,9,10,10a-dodeca­hydro­phenan­threne-1-carboxylic acid

The title compound, C20H32O2, has been isolated from hydrogenated rosin. There are two independent mol­ecules in the asymmetric unit. In each mol­ecule, the cyclo­hexane ring assumes a chair conformation, while the two cyclo­hexene rings adopt half-chair and envelope conformations. Inter­molecular O—H⋯O hydrogen bonding between carboxyl groups links pairs of independent mol­ecules into dimers

BOURNE: Bootstrapped Self-supervised Learning Framework for Unified Graph Anomaly Detection

Graph anomaly detection (GAD) has gained increasing attention in recent years due to its critical application in a wide range of domains, such as social networks, financial risk management, and traffic analysis. Existing GAD methods can be categorized into node and edge anomaly detection models based on the type of graph objects being detected. However, these methods typically treat node and edge anomalies as separate tasks, overlooking their associations and frequent co-occurrences in real-world graphs. As a result, they fail to leverage the complementary information provided by node and edge anomalies for mutual detection. Additionally, state-of-the-art GAD methods, such as CoLA and SL-GAD, heavily rely on negative pair sampling in contrastive learning, which incurs high computational costs, hindering their scalability to large graphs. To address these limitations, we propose a novel unified graph anomaly detection framework based on bootstrapped self-supervised learning (named BOURNE). We extract a subgraph (graph view) centered on each target node as node context and transform it into a dual hypergraph (hypergraph view) as edge context. These views are encoded using graph and hypergraph neural networks to capture the representations of nodes, edges, and their associated contexts. By swapping the context embeddings between nodes and edges and measuring the agreement in the embedding space, we enable the mutual detection of node and edge anomalies. Furthermore, we adopt a bootstrapped training strategy that eliminates the need for negative sampling, enabling BOURNE to handle large graphs efficiently. Extensive experiments conducted on six benchmark datasets demonstrate the superior effectiveness and efficiency of BOURNE in detecting both node and edge anomalies

2-Hydr­oxy-6,6-dimethyl­bicyclo­[3.1.1]heptane-2-carboxylic acid

The title compound, C10H16O3, with a bicyclo­[3.1.1]heptane unit, was obtained by oxidation of β-pinene. The asymmetric unit contains two independent mol­ecules with similar geometry: the six-membered rings in both mol­ecules adopt envelope conformations. In the crystal, the independent mol­ecules exist as O—H⋯O hydrogen-bonded dimers. The dimers are linked into helical chains along the b axis by O—H⋯O hydrogen bonds

15-Hydroxy­ethyl-19-isopropyl-5,9-dimethyl-14,16-dioxo-15-aza­penta­cyclo­[10.5.2.01,10.04,9.013,17]nona­dec-18-ene-5-carboxylic acid

The title compound, C26H37NO5, which was synthesized from monoethano­lamine and maleopimaric acid, consists of two fused and unbridged cyclo­hexane rings. They form a trans ring junction with a chair conformation. The two methyl groups are in axial positions. In the crystal, inter­molecular O—H⋯O hydrogen bonds link adjacent mol­ecules into a layer structure. Two C—H⋯O interactions are also present

2-[(1S,3S)-3-Acetyl-2,2-dimethyl­cyclo­butyl]-N-(m-tol­yl)acetamide

The title compound, C17H23NO2, contains two chiral centres and was synthesized from 2-(3-acetyl-2,2-dimethyl­cyclo­butyl)acetic acid and m-toluidine. The cyclobutane ring is not flat but flexed as though folded from the dimethyl-substituted C atom to the unsubstituted C atom, with a dihedral angle of 25.9°. The crystal structure is stabilized by N—H⋯O and C—H⋯O hydrogen-bonding inter­actions

16-Isopropyl-5,9-dimethyl­tetra­cyclo­[10.2.2.01,10.04,9]hexa­dec-15-ene-5,14-dimethanol

The title compound, C23H38O2, a tetra­cyclo­[10.2.2.01,10.04,9] hexa­decane structure, crystallized with four independent mol­ecules in the asymmetric unit. In the crystal, these independent mol­ecules are linked by O—H⋯O hydrogen bonds, forming a polymeric chain propagating in [100

SYNTHESIS OF CYCLOBUTANE ANALOGUES

2-(3-Acetyl-2,2-dimethylcyclobutyl)acetic acid (pinonic acid) was synthesized using α-pinene as raw material and potassium permanganate as oxidant. This compound reacted with substituted aniline to produce eight kinds of derivatives with cyclobutane moiety. The yields of the cyclobutane analogues ranged from 24.9 to 78.2 %. KEY WORDS: Cyclobutane analogues, Pinonic acid, Oxidation Bull. Chem. Soc. Ethiop. 2009, 23(1), 135-139

N-Benzyl­idenenordehydro­abietylamine

The title compound [systematic name: (1R,4aS,10aR,E)-N-benzyl­idene-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octa­hydro­phenanthren-1-amine], C26H33N, has been synthesized from nor-dehydro­abietylamine and benzaldehyde. The two cyclo­hexane rings form a trans ring junction with classic chair and half-chair conformations, respectively, the two methyl groups are on the same side of tricyclic hydro­phenanthrene structure. The dihedral angle between two benzene rings is 44.2 (4)°. The C=N bond is in an E configuration

16-Isopropyl-5,9-dimethyl­tetra­cyclo­[10.2.2.01,10.04,9]hexa­dec-15-ene-5,13,14-tricarboxylic acid dimethyl­formamide disolvate

The title compound, C24H34O6·2C3H7NO, which was isolated from fumaric-modified rosin, has four asymmetrically fused six-membered rings and three carboxylic acid substituents. It contains two fused and unbridged cyclo­hexane rings, which form a trans ring junction with a chair conformation. The asymmetric unit includes one fumaropimaric acid and two dimethyl­formamide mol­ecules. The crystal structure is stabilized through inter­molecular O—H⋯O hydrogen bonds between dimethyl­formamide and fumaropimaric acid