IDEA-AI4S/ChemO huggingface dataset:
IChO-2025_1
Points: 34
context: Sesquiterpenes have the formula C_{15}H_{24}. They are secondary metabolites in plants and both deter insects which eat plants and attract animals which eat the insects. Isocaryophyllene (i-Cy) is a sesquiterpene found in oregano, rosemary, pepper, and cloves. The structural formula of i-Cy can be determined by performing various reactions and analysing the products as shown in the figure.
IChO-2025_1.1
Type: Structure Construction
Points: 7
Question: context: Draw the structures of i-Cy, A, and B.
requirement: Convert the drawn structures to SMILES format (stereochemistry not required).
parsing_note: The reaction diagram has been converted to reaction_scheme.
reaction_scheme: reactant_name: i-Cy
reactant_formula: C_{15}H_{24}
conditions: H_{2}, Pd/C
product_name: B
product_formula: C_{15}H_{28}
reactant_name: i-Cy
reactant_formula: C_{15}H_{24}
conditions: (1) BH_{3}/THF (1/3 equiv.), THF ; (2) H_{2}O_{2}, NaOH, H_{2}O
product_name: A
product_formula: C_{15}H_{26}O
reactant_name: i-Cy
reactant_formula: C_{15}H_{24}
conditions: (1) O_{3}, CH_{2}Cl_{2}; (2) Zn, CH_{3}COOH
product_smiles: C=O
CC1([C@]([H])(CCC(C)=O)[C@@](C(CCC([H])=O)=O)(C1)[H])C
reactant_name: A
reactant_formula: C_{15}H_{26}O
conditions: (1) O_{3}, CH_{2}Cl_{2}; (2) Zn, CH_{3}COOH
product_name: C
product_smiles: CC1(C)[C@]([C@@]([H])([C@](CO)(CCC([H])=O)[H])C1)([H])CCC(C)=O
Answer: name: A
smiles: CC1=CCC[C@@H](CO)[C@]2([H])[C@]([H])(C(C)(C)C2)CC1
alternative_smiles: CC1=CCCC(CO)C2([H])C([H])(C(C)(C)C2)CC1
points: 2
grading: partial_credit: condition: if missing a carbon atom in the ring or added another carbon atom in the ring.
deduction: -1
notes: Stereochemistry will not be marked for A.
name: B
smiles: CC1CC[C@@]([H])(C(C)(C)C2)[C@@]2([H])C(C)CCC1
alternative_smiles: CC1CCC([H])(C(C)(C)C2)C2([H])C(C)CCC1
points: 2
grading: partial_credit: condition: If the structure is incorrect, but consistent with isocaryophyllene (and 2 equivalents of $H_2$ are added).
deduction: 0
notes: Also 2 pt  Stereochemistry will not be marked for B.
name: i-Cy
smiles: C/C(CC[C@]1([H])[C@]2([H])CC1(C)C)=C/CCC2=C
alternative_smiles: C/C(CCC1([H])C2([H])CC1(C)C)=C/CCC2=C
points: 3
grading: partial_credit: condition: If missing a carbon atom or added another carbon atom in the ring.
deduction: -1
condition: If a ring is made by combining two other C atoms and added a methyl to the other carbon
deduction: -1
condition: If no second ring is present; only added CH3 to all/one/two carbonyls in the right-hand structure.
deduction: -2
notes: The trans-isomer gets full marks. Stereochemistry will not be marked for i-Cy.
IChO-2025_1.2
Type: Qualitative Identification
Points: 3
Question: context: Circle the stereocentres in compound C and assign them as R or S.
parsing_note: The structure in the image has been converted to SMILES format.
smiles: [H][C@@]1(C(C)(C)C[C@]1([H])[C@@](CCC([H])=O)(CO)[H])CCC(C)=O
requirement: 1) Count only carbon atoms (C) in the SMILES string from left to right, ignoring all other atoms like H, O, N. Number each carbon sequentially as C-1, C-2, C-3, etc. 2) Assign R or S configuration to each. Output format: 'C-X: R/S'.
Answer: context: C-1: R, C-6: S, C-7: R
grading: partial_credit: condition: Each centre not correctly circled
deduction: -1
condition: Each descriptor not correct
deduction: -0.5
condition: Each incorrect centre is circled.
deduction: -1
notes: Minimum score is 0
points: 3
IChO-2025_1.3
Type: Structure Construction
Points: 6
Question: context: Clovene (Cv) can be synthesised from i-Cy under acid catalysis. The synthesis of Cv starts from compound D. Draw the structures of compounds E and F.
parsing_note: The reaction diagram has been converted to reaction_scheme.
requirement: Convert the drawn structures to SMILES format (stereochemistry not required).
reaction_scheme: reactant_name: D
reactant_smiles: C[C@@]1(CCC2)C=CC(O)[C@@]2(CC(OC)=O)C1
conditions: H^{+} (cat.)
product_name: E
product_formula: C_{12}H_{16}O_{2}
reactant_name: E
reactant_formula: C_{12}H_{16}O_{2}
conditions: 1) LiAlH_{4}, Et_{2}O; 2) H^{+}, H_{2}O
product_name: F
reactant_name: F
step_name: 1
product_name: G
product_smiles: C[C@]1(C=C2)CCC[C@](CCO)(C1)C2=O
reactant_name: G
reactant_smiles: C[C@]1(C=C2)CCC[C@](CCO)(C1)C2=O
step_name: 2
product_name: H
product_smiles: C[C@]1(C=C2)CCC[C@](CC(O)=O)(C1)C2=O
Answer: name: E
smiles: O=C1C[C@@]23C[C@@](CCC3)(C)C=C[C@H]2O1
alternative_smiles: O=C1CC23CC(CCC3)(C)C=CC2O1
points: 3
grading: partial_credit: condition: If the structure is not cyclic and only the ester is removed.
deduction: -2
notes: Stereochemistry will not be marked.
name: F
smiles: O[C@H]1[C@@]2(CCO)C[C@@](CCC2)(C)C=C1
alternative_smiles: OC1C2(CCO)CC(CCC2)(C)C=C1
points: 3
grading: partial_credit: condition: If reducing the ester to an aldehyde (and alcohol).
deduction: -2
notes: Stereochemistry will not be marked.
IChO-2025_1.4-5
Type: Qualitative Identification
Points: 2
Question: context: Clovene (Cv) can be synthesised from i-Cy under acid catalysis. The synthesis of Cv starts from compound D. For steps '1' and '2' several reagents could be considered. For example: A. PCC B. K_{2}Cr_{2}O_{7}, H_{2}SO_{4}, H_{2}O C. MnO_{2} D. (i) OsO_{4} , (ii) KHSO_{3} From the reagents above, tick which one(s) would be suitable for step '1'. From the reagents above, tick which one(s) would be suitable for step '2'.
parsing_note: The structure in the image has been converted to SMILES format.
smiles: name: PCC
components: c1cc[nH+]cc1
[O-][Cr](Cl)(=O)=O
requirement: Convert the drawn structures to SMILES format (stereochemistry not required).
Answer: name: step 1
choice: C
points: 1
name: step 2
choice: B
points: 1
IChO-2025_1.6
Type: Structure Construction
Points: 8
Question: context: Draw the structures of compounds I, J, and K.
parsing_note: The reaction diagram has been converted to reaction_scheme.
requirement: Convert the drawn structures to SMILES format (stereochemistry not required).
reaction_scheme: reactant_name: H
reactant_smiles: C[C@]1(C=C2)CCC[C@](CC(O)=O)(C1)C2=O
conditions: 1) H_{2}, Pd/C; 2) CH_{3}OH H^{+}
product_name: I
reactant_name: I
conditions: 1) HOCH_{2}CH_{2}OH, H^{+}; 2) NaOH, H_{2}O
product_name: J
reactant_name: J
conditions: 1) SOCl_{2}; 2) Et_{2}CuLi; 3) H^{+}, H_{2}O
product_name: K
reactant_name: K
conditions: 1) NaOH, H_{2}O, Δ
intermediate_smiles: CC1=C2CC[C@]3(CCC[C@]2(CC1=O)C3)C
product_name: Cv
product_smiles: CC1([C@@]2(CC[C@]3(CCC[C@]2(C=C1)C3)C)[H])C
Answer: name: I
smiles: O=C1C=C[C@]2(CCC[C@]1(CC(OC)=O)C2)C
alternative_smiles: O=C1C=CC2(CCCC1(CC(OC)=O)C2)C
points: 3
grading: partial_credit: condition: if double bond is not reduced.
deduction: -2
condition: if ester is not formed
deduction: -1
notes: Stereochemistry will not be marked for I. Minimum score is 0 pt.
name: J
smiles: CC1CC[C@@]([H])(C(C)(C)C2)[C@@]2([H])C(C)CCC1
alternative_smiles: CC1CCC([H])(C(C)(C)C2)C2([H])C(C)CCC1
points: 2
grading: partial_credit: condition: if acetal group is incorrect/not present.
deduction: -1
condition: if original ester is still present; protective group is in place.
deduction: -1
condition: if ester is formed with ethylene glycol.
deduction: -1.5
notes: Stereochemistry will not be marked for I. Minimum score is 0 pt.
name: K
smiles: O=C1C=C[C@]2(CCC[C@]1(CC(CC)=O)C2)C
alternative_smiles: O=C1C=CC2(CCCC1(CC(CC)=O)C2)C
points: 3
grading: partial_credit: condition: If acetal protecting group is still present.
deduction: -1
condition: If acid is turned into acid chloride and protective group is removed.
deduction: -2
condition: If five-membered ring is already formed with an alcohol group still present.
deduction: -2
notes: Stereochemistry will not be marked for I. Minimum score is 0 pt.
IChO-2025_1.7-8
Type: Structure Construction
Points: 4
Question: context: Humulene (Hu) is another sesquiterpene. It can be converted to  α-caryophyllene alcohol (α-Ca), which is similar in structure to Cv. This conversion is an acid-catalysed hydration reaction which takes place via multiple intermediate structures. Incomplete structures of some intermediates, X and Y, are shown. The transformation from Hu to X is an acid-catalysed isomerisation reaction. Intermediate Y is charged.
parsing_note: The reaction diagram has been converted to reaction_scheme.
requirement: Convert the completed structures to SMILES format.
reaction_scheme: reactant_name: Hu
reactant_smiles: CC1(C)C/C=C(C)/CC/C=C(C)/C/C=C/1
conditions: H^{+} (cat.)
product_name: X
product_smiles: CC1CCC(C)(C)CCC(C)CCC1
reactant_name: X
reactant_smiles: CC1CCC(C)(C)CCC(C)CCC1
conditions: +H^{+}
product_name: Y
product_smiles: CC1(CC2C3(C)CCCC(C)C3C2C1)C
reactant_name: Y
reactant_smiles: CC1(CC2C3(C)CCCC(C)C3C2C1)C
conditions: 1) H_{2}O, -H^{+}
product_name: α-Ca
product_smiles: CC1(C)CC(C2C1)C3(CCCC2(C3O)C)C
Answer: name: X
smiles: CC1=C\CC/C(C)=C/CC(C)(C)C/C=C/1
alternative_smiles: C/C1=C/C=C/C(C)(C)C/C=C(C)/CCC1
points: 2
grading: partial_credit: condition: for each mistake down to zero.
deduction: -1
condition: if all double bonds are mirrored.
deduction: -1
name: Y
smiles: CC1(C)CC2C3(CCC[C+](C3C2C1)C)C
points: 2
grading: partial_credit: condition: if any other charge or group has been added to the structure.
deduction: -2
IChO-2025_1.9
Type: Qualitative Identification
Points: 2
Question: context: Five carbon atoms are circled in Hu. Through understanding the mechanism we can determine where these five carbon atoms end up in α-Ca. Circle the five corresponding carbon atoms in α-Ca which are circled in Hu.
smiles: Hu: CC1(C)CC/C=C(C)/CC/C=C(C)/C/C=C/1
Y: CC1(CC(C2(C)CCCC3(C)C2O)C3C1)C
parsing_note: The structure in the image has been converted to SMILES format.
requirement: 1) Count only carbon atoms (C) in the SMILES string from left to right, ignoring all other atoms like H, O, N. Number each carbon sequentially as C-1, C-2, C-3, etc. 2) In Hu, C-6, C-7, C-12, C-14, C-15 are circled based on Hu smiles. 2) Give the five corresponding carbon atoms in α-Ca which are circled in Hu, Output format: 'C-X, C-X'.
Answer: context: C-5, C-6, C-8, C-12, C-13
grading: partial_credit: condition: if five circles are correct.
deduction: 0
condition: if four circles are correct and one incorrect or missing.
deduction: -1
condition: for more than five carbons circled or two or more incorrect/missing.
deduction: -2
notes: Minimum score is 0
points: 2